U.S. Customs and Border Protection officials held up dozens of Iranians and Iranian Americans at a Washington state border crossing over the weekend, detaining some for up to 12 hours, in the wake of government-issued warnings about Iranian security threats, immigrant advocates and travelers said.

Advocates from the Council on American-Islamic Relations and the National Iranian American Council reported that Iranian green-card holders and U.S. citizens of Iranian descent were being targeted for extensive questioning and delays at the Blaine, Wash., border crossing on Saturday. The organizations said many travelers were held into the early hours of Sunday morning.

A CBP spokesman denied that Iranians were being delayed based on their national origin. CBP officials said the extended wait times — of two to four hours — at that port of entry Saturday were the combined result of lowered holiday staffing, high border traffic and an “enhanced posture” of security implemented at border crossings because of “the current threat environment.”

U.S. officials warned last week that Tehran could retaliate for Friday’s targeted killing of one of Iran’s most prominent officials, Qasem Soleimani, an Iranian Revolutionary Guard Corps commander.

The Department of Homeland Security, which oversees U.S. border and immigration authorities, on Saturday updated its security advisory on Iran, warning that although it had “no information indicating a specific, credible threat” to the United States, Iran and its partners had “demonstrated the intent and capability to conduct operations in the United States.”

Such retaliation could come in the form of cyberattacks against U.S.-based targets or acts of violence waged by “Homegrown Violent Extremists,” DHS warned. “An attack in the homeland may come with little or no warning.”

The Post's Mustafa Salim saw anger and grief at a funeral Jan. 4 in Baghdad for Iran's Maj. Gen. Qasem Soleimani and paramilitary leader Abu Mahdi al-Muhandis. (Mustafa Salim/The Washington Post)

Immigrant and civil rights advocates said Sunday that U.S. government suspicion of Iranians had translated into targeted delays at the Blaine port of entry. Dozens of U.S. residents of Iranian descent were crossing back into the country this weekend after traveling to Canada for work or tourism, including a recent concert in nearby Vancouver that featured an Iranian pop star.

The Seattle metropolitan area — about 100 miles south of the Blaine crossing — is home to a large Iranian diaspora.

Masih Fouladi, the executive director of CAIR-Washington and an American Iranian dual national, said he spoke to members of three families who had been detained for between eight and 11 hours at the Peace Arch crossing in Blaine. Those held for what CBP calls “secondary questioning” were there for so long that CBP officials eventually ordered pizzas for them, Fouladi said.

The travelers said CBP officials asked detailed questions about their backgrounds and requested contact information for relatives in Iran. Some were asked whether they or any relatives had served in the Iranian military — jarring inquiries for some who had immigrated to the United States decades ago, before the modern state of Iran and its Iranian Revolutionary Guard Corps existed.

A U.S.-born citizen who was traveling with her Iranian-born parents — both also U.S. citizens — said her family was held for nearly 12 hours as they were trying to return from a vacation in Canada.

Border agents never explained why they had pulled the family aside, she said, but they asked them several questions about a country her parents left decades ago, including what courses her parents took in college.

“My dad was like, ‘I haven’t been in college for years — I don’t know what courses I took,’ ” the woman said in an interview with reporters, speaking on the condition of anonymity because she fears government retribution.

When her family and others at the Peace Arch crossing complained or asked how much longer they would be waiting, the agents seemed confused and bewildered by their own mission, she said.

“We were there for so long that three shifts of officers went through. And every time a new shift came, they were clueless,” she said. “They would say, ‘Your case is being processed.’ And we’re like, what do you mean? We’re not criminals — what case?”

Tensions between the U.S. and Iran escalated with no relief in sight after a U.S. drone strike killed Qasem Soleimani, an Iranian military commander, on Jan. 3. (The Washington Post)

Even though the killing sparked an immediate flare-up in U.S.-Iranian tensions, she said she and her family never considered the possibility that it would affect them as Americans of Iranian heritage.

“We didn’t think twice about how it would affect us, that this would actually be a threat to us, personally,” she said, noting that she and her family go to Canada “all the time.”

Matthew Leas, a CBP spokesman, disputed such accounts, including claims on social media that the agency had been directed to make it more difficult than usual for those with connections to Iran to cross into the United States.

“Social media posts that CBP is detaining Iranian-Americans and refusing their entry into the U.S. because of their country of origin are false,” Leas said in a statement. “Reports that DHS/CBP has issued a related directive are also false.”

CBP officials said that waits at the port of entry in Blaine had increased to an average of two hours Saturday evening but that times were back down to about 40 minutes by Sunday morning.

“Based on the current threat environment, CBP is operating with an enhanced posture at its ports of entry to safeguard our national security and protect the America people while simultaneously protecting the civil rights and liberties of everyone,” the agency said in a statement. “CBP routinely adjusts staffing and operations to maintain the dual missions of border security and facilitation of lawful trade and travel. Processing times are the result of the current circumstances, including staffing levels, volume of traffic, and threat posture.”

U.S. Rep. Pramila Jayapal (D), who represents the Seattle area, said Monday that her staff had spoken to a number of Iranian-Americans who had been detained at the crossing Saturday night, and was in the process of “trying to get to the bottom of exactly what was told to CBP officials” that led to those detentions.

“I wouldn’t call it just additional scrutiny because they had their passports taken away, they were not allowed to leave, so they were held in some form of detention at the Peace Arch Border crossing,” she said. “It appears that was as the result of some sort of directive. I understand CBP has said no such thing occurred. But it is difficult to believe that when you listen to the multiple accounts of what happened. It is also difficult to believe that this was just a question of short staffing at the border … because, in fact, there were clearly many people being processed. The only people who seemed to be pulled aside and held back and detained in some form or fashion were people of Iranian heritage.”

“Even the Border Patrol agents themselves talked about following orders,” Jayapal said. “So there was some sort of order.”

Fouladi and other advocates who spoke to Iranians and Iranian Americans experiencing travel delays said that the problems seemed largely limited to the Blaine crossing, but that they had received some reports of similar experiences at a few airports.

Ryan Costello, policy director for the National Iranian American Council, said he spoke to one such traveler — a naturalized U.S. citizen — after U.S. immigration authorities pulled him aside at the Calgary airport before he could board a flight to the United States.

The man told Costello that he was bewildered by the questions the agents asked, including whether he had served in the Iranian military.

“He hadn’t been to Iran since 1978,” Costello said. “He initially thought they meant U.S. military service because he had been here for so long.”

Advocates and attorneys said Monday that the delays seem to have dissipated.

Jorge Barón, executive director of the Northwest Immigrant Rights Project, said there were still members of at least three families with ties to Iran — most of them U.S. citizens — undergoing secondary questioning related to Iran when he arrived at the crossing on Sunday afternoon. Those families waited between an hour and 2½ hours, he said.