Stepping up the urgency of American response, the White House on Friday called on Iran to release a jailed American pastor facing a trial that could send him to the gallows.

Saeed Abedini, a native of Iran and a naturalized American citizen, is expected to enter one of Iran’s revolutionary courts Monday to face accusations that he is a threat to national security. His lawyers say he faces a lengthy prison term and even the death penalty at the hands of one of Iran’s most notoriously severe judges.

Abedini’s supporters in the United States say he was in Iran last summer to complete construction of an orphanage when members of Iran’s Revolutionary Guard snatched him off a bus, confiscated his passports, and threw him in prison. Since then, they say, the pastor has been subjected to solitary confinement and beatings.

It wasn’t until last week that Abedini’s attorney in Iran got access to his case file and discovered his client would be brought into court as soon as Jan. 21, according to the U.S. Commission on International Religious Freedom, an advisory panel to the administration and Congress.

Iran’s Revolutionary Court is not exactly transparent, so it’s not known what precise charges Abedini will face, said Tiffany Barrans, international legal director for the American Center for Law and Justice, a Washington, D.C.-based attorney group that uses litigation to press for religious and speech freedom. But Barrans said it was Abedini’s background as an organizer of house churches in Iran that has angered the government, and for which he will be tried. Christianity, she said, is regarded in official Iranian circles as a security threat because it can entice young people away from Islam, which is Iran’s official religion.

During a routine press briefing Tuesday, White House Press Secretary Jay Carney had no response to a question seeking President Obama’s position on Abedini’s trial. On Friday, U.S. National Security Council spokesman Tommy Vietor issued a statement demanding Abedini’s release.

“We remain troubled by the case of U.S. citizen Saeed Abedini, who was arrested by Iranian officials more than three months ago on charges relating to his religious beliefs,” Vietor said in the statement. “We call upon Iranian authorities to release him immediately.”

It is the first official remark by the administration about Abedini’s case. The ACLJ called it a “significant step forward in the effort to save this American pastor.”

On Tuesday, 11 members of the U.S. Senate and 37 members of the House of Representatives sent a letter to Secretary of State Hillary Clinton urging the U.S. to bring whatever diplomatic pressure it can to persuade Iran to release Abedini. The United States and Iran do not have diplomatic ties, so any pressure would have to be applied indirectly.

“Your voice can motivate countries and international organizations that have diplomatic relations with Iran into action,” the Senate letter read. “We strongly encourage the State Department to exhaust all efforts to secure Mr. Abedini’s prompt return. Saeed’s efforts to provide humanitarian relief and exercise fundamental human rights should be applauded not condemned. We should not stand idly by while the Iranian regime arbitrarily persecutes a U.S. citizen who has committed no crime.”

“There is still a great deal of good that the State Department can and should do on behalf of Mr. Abedini, one of our own citizens,” the letter from the House members read. “Strong and sustained advocacy from the State Department would do much to rally the voice of the world against this wrongful detainment.”

Barrans said the U.S. could exert leverage through countries such as Brazil and Turkey, which have diplomatic relations with America and strong economic ties to Iran.

“We can reach out to multiple countries to just put in an inquiry on pastor Saeed,” she told World Watch Monitor. “If Iran takes enough inquiries from friends, they will take notice of Saeed’s case and ensure justice is done, whether that means he receives a fair trial, or they take him out of the Revolutionary Court system, or if they release him immediately.”

The Commission on International Religious Freedom, comprised of presidential and congressional appointees, demanded Abedini’s release in a statement issued Wednesday:

“The national security charges leveled against Mr. Abedini are bogus and are a typical tactic by the Iranian government to masquerade the real reason for the charges: to suppress religious belief and activity of which the Iranian government does not approve,” Commission Chairwoman Katrina Lantos Swett said.

The commission and the American Center for Law and Justice both say Abedini’s case has been assigned to Iran’s Revolutionary Court, which answers to the country’s supreme leader, Grand Ayatollah Seyyed Ali Hosseini Khamenei. The judge in the case, Abbas Pir-Abbassi, is known in the West primarily for his harsh sentences, including execution, of students who participated in protests after the 2009 elections. The European Union has branded Pir-Abbassi, among other Iranian judges, a human-rights violator. The U.S. religious-freedom commission has recommended that the State Department make a similar declaration, but it has yet to do so.

Even so, “our government is very well aware of how this man abuses his position of authority,” said Barrans of the ACLJ. “It is great cause for concern.”

Barrans said Iranian lawyers quail at the prospect of representing human-rights cases before Pir-Abbassi. “Most lawyers know your chances of being thrown in prison merely for representing someone like Saeed are greatly increased,” she said, adding that Abedini should expect no due process at all during his trial.

Both Abedini, 32, and his wife, Nagmeh, were born Muslim in Iran. She moved to the United States as a child, obtained U.S. citizenship, converted to Christianity, relocated to Idaho with her family, and eventually returned to Iran to connect with her extended family, said Lauren Phillips, coordinator for international outreach for Cavalry Chapel of Boise, where the couple are members. Though ordained for his work planting house churches in Iran, Abedini is not active as a pastor in his home church, Phillips said.

In Iran Nagmeh met Abedini, who had converted to Christianity in 2000 and was helping to start house churches. Married in 2004, they moved to Idaho in 2005 after Abedini endured an interrogation session over his church activities, Barrans said. As the spouse of an American citizen, Abedini too was granted citizenship.

Barrans said Abedini continued to visit Iran, under a 2009 agreement with Iran’s intelligence police. The deal, she said, was that Abedini could come and go from Iran to build an orphanage, but only if he stayed out of church planting. By last July, he had visited Iran eight times.

“He had no reason to expect the ninth trip would look any different,” she said.

But on Sept. 26 he was arrested by Revolutionary Guard soldiers, and has been kept at Evin prison, where many political prisoners are held.

Sometime between that eighth and ninth visit, Barrans said, police jurisdiction over Iranian Christian life shifted from the politically controlled intelligence police to the religiously controlled Revolutionary Guard, which answers directly to Iran’s grand ayatollah. The government has become increasingly aggressive about driving Christianity out of Iran, she said.

So aggressive, she said, that the prosecution intends to use as evidence against Abedini a series of satellite broadcasts to Iranian Christians in 2005.

“Some of the evidence against Saeed that is going to be brought against him are actions he took on U.S. soil,” Barrans said.

In a Jan. 10 letter that the ACLJ said Abedini was able to send from Evin, he describes being held for three months in a constantly lighted room, and provided a brief glimpse of the sky once per week.

“One day I am told I will be freed and allowed to see my family and kids on Christmas (which was a lie) and the next day I am told I will hang for my faith in Jesus,” the letter states. “One day there are intense pains after beatings and interrogations, the next day they are nice to you and offer you candy.”

Nagmeh told Boise television station KBOI on Thursday that she has been able to speak by phone with her husband.

“It was weeks and weeks before I even heard his voice,” she told the TV station. “He shared that he really misses the kids, and me, and really wants to be home.” The couple has a daughter, 6-year-old Rebekkah, and a son, 4-year-old Jacob.

“I wanted to tell him that we’re fighting for him here, but I couldn’t,” she said. “I didn’t know if it was safe. I know that his phone is being listened to.”

Phillips said Calvary Chapel of Boise plans a prayer service with the Abedini family on Sunday.

“We just want to see Saeed back home,” she said.