Authorities across the Washington region are boosting security at military bases, Arlington Cemetery and sites along the Mall after threats by Iran to retaliate against the United States for the killing of Maj. Gen. Qasem Soleimani.

In some cases, entry gates at military facilities have been closed, and officials are carrying out more thorough identity checks. A spokesman for the U.S. Park Police said the agency’s uniformed officers will have a more visible presence because of the tensions with Iran.

“There’s no specific threats,” said Sgt. Eduardo Delgado, the Park Police spokesman. “It’s just an abundance of precaution.”

But the rollout of the enhanced security has not been smooth in every case, leaving some people facing a chaotic return to work at the beginning of the new year. The Navy command that runs Walter Reed National Military Medical Center in Bethesda modified some of its new precautions and issued a lighthearted mea culpa on its Facebook page Monday evening after the security changes caused monstrous traffic in the area that morning.

“Today’s traffic was awful. It was horrible,” the post read. “It looked at normal D.C. Monday traffic and said, ‘Hey, watch this!’ ”

Nevertheless, officials wrote that the enhanced security was necessary to keep people safe.

Last week, President Trump ordered the drone strike that killed Soleimani, Iran’s most powerful military commander. Iran’s leaders quickly promised to take revenge. And an Iranian official said Tuesday that the country was considering 13 scenarios for retaliation and had U.S. bases in the Middle East under surveillance. On Tuesday night, Iran launched missiles at two bases in Iraq that house American troops.

Over the weekend, the Department of Homeland Security issued a bulletin warning that Iran and its allies have “demonstrated the intent and capability to conduct operations in the United States.” But much of the focus has been on a cyberattack, rather than a physical one.

“At this time we have no information indicating a specific, credible threat to the Homeland,” the department said in the bulletin, issued Saturday.

Officials said they are still taking precautions but in most cases declined to tie them directly to the situation with Iran.

The enhanced security at military bases in the region is in line with a directive from U.S. Northern Command, which oversees facilities in the United States, to impose “additional force protection condition measures to increase security and awareness for all installations.”

Walter Reed and Joint Base Andrews in Maryland, Joint Base Anacostia-Bolling in the District, and Arlington National Cemetery, Joint Base Myer-Henderson Hall and Marine Corps Base Quantico in Virginia all issued public updates on security measures this week.

D.C. Mayor Muriel E. Bowser (D) said Friday that her team knew of no specific threats but that they were coordinating with federal agencies to monitor what was happening domestically and overseas.

Officials at Joint Base Andrews said in a statement that they reviewed the base’s security over the past week, but they declined to describe most of the steps they were taking.

On its website, the base, which is home to Air Force One, did outline new procedures beginning Tuesday for visitors traveling with someone who holds a Defense Department ID to undergo a background check before entering the post.

“We are confident Joint Base Andrews is still one of the safest places in the world to live and work, and we will continue working hard to keep it that way,” the statement read.

At Walter Reed National Military Medical Center, staff and visitors complained of waits of an hour or more to get inside and bad traffic on surrounding streets after the Navy command that runs the facility decided to close most gates.

“The long time was one issue, but people were driving very aggressively and unsafe,” one woman wrote on the command’s Facebook page. “There were illegal turns, cutting people off, honking, blocking traffic in both directions/blocking the box, and it was just generally not a good and potentially hazardous situation.”

One man wrote that traffic was backed up well into late Monday morning: “I understand the security concerns but first responders will have difficulty getting through.”

Late Monday, officials changed the security measures, deciding to open some more gates for Tuesday’s commute.

“It was a REALLY bad day for traffic and yes, the security changes at NSA Bethesda were to blame,” the command’s Facebook post read.

The situation at Marine Corps Base Quantico was similarly bad after security staff at the facility began a more thorough check of IDs. Facebook users continued to share complaints about their experience trying to get onto the facility Tuesday.

“I’m seriously debating on just putting in two weeks of leave,” one woman wrote. “Waiting over 2 and a half hours for a typical 15 minute commute is unacceptable.”

Like others, she complained about sitting in a line of cars while vehicles zipped by at high speeds.

“This is also putting us in more danger due to heightened road hazards and making us Sitting ducks,” she wrote.

“Fully support the safety concerns but there has to be Better way,” another woman wrote.

Elsewhere, the disruptions appear to have been less severe.

Arlington National Cemetery began checking every visitor’s ID, and a spokeswoman said that there is a more visible law enforcement presence but that visits haven’t been affected.

“The vast majority of visitors are arriving with their IDs in hand and ready to be verified, minimizing wait times for those entering the cemetery,” said Ashley Topolosky, the spokeswoman.

Delgado, the Park Police spokesman, said the agency was taking other steps that would not be made public but added that visitors to the Mall should not expect to be affected.

And Jeremy Brooks, a spokesman for the Navy command in Bethesda, said Tuesday had been much better than Monday, even though there were still some backups.

“We understand that yesterday was very frustrating for a lot of people,” he said.