WASHINGTON — Major U.S. airlines are barring passengers on District of Columbia-bound flights from traveling with firearms ahead of next week’s presidential inauguration – the latest in a series of steps air carriers have taken amid concerns about passenger safety.

In a statement, Delta said it made the decision after weighing the violence at the U.S. Capitol last week alongside the airline’s “unwavering commitment to the safety of customers and our people.”

“Nothing is more important than doing our part to keep people safe,” the airline said.

Alaska Airlines’ ban will take effect Friday; American, Frontier, Delta and United will begin theirs Saturday. The policy will remain in effect through Jan. 23, the carriers said. Airlines said exceptions will be made for law enforcement officials with proper credentials and active duty military traveling on orders.

Under Transportation Security Administration rules, passengers can bring unloaded firearms on flights, but they must be placed inside checked baggage and secured in locked, hard-sided cases. Passengers must tell the airline that they are traveling with firearms during the check-in process. Ammunition can be carried but also must be transported in checked baggage.

Alaska Airlines, which banned 14 people for unruly behavior on a flight from Washington to Seattle the day after the attack on the Capitol, also said it will limit the number of seats it sells on flights to and from the nation’s capital. Passengers on those flights will be required to remain seated during the first and last hour of their flights.

The heightened concern for safety on airplanes and at airports comes after last week’s violence and the upcoming inauguration of President-elect Joe Biden. Some pro-Trump groups have pledged to return to the nation’s capital.

Videos circulating on social media before and after the riots captured the tension involving those who support the president’s unfounded allegations that the election was stolen.

Sen. Mitt Romney, D-Utah, was accosted by supporters of Trump as he waited for his flight to Washington the day before the riots, and later aboard the aircraft. On Friday, Sen. Lindsey Graham, R-S.C., was escorted by police from Reagan National Airport after he was heckled and called a traitor for not supporting the president’s baseless claims.

In addition to the ban on firearms, airlines also pledged stepped up enforcement of mask requirements. Carriers have banned more than 1,600 people for refusing to wear masks. United said it banned 60 people last week for refusing to wear face coverings, while the airline has banned more than 600 people overall.

Carriers said they will have additional staff at key hubs, including airports in the District region. Crew members are staying at hotels outside downtown Washington.

The airlines’ actions add to those taken by the Federal Aviation Administration, which this week warned passengers they could face stiff fines or jail time if they act out or refuse to cooperate with crew members’ orders, including requirements that they wear masks. On Wednesday FAA Administrator Steve Dickson signed an order creating a special enforcement program focused on those who refuse to comply. Those who are cited could face jail time or fines of up to $35,000.

Others involved in violence at the Capitol could find themselves barred from flying.

After calls from union leaders and lawmakers, the Federal Bureau of Investigation said it will consider putting individuals who participated in the Jan. 6 insurrection on the federal a no-fly list.

Members of the House Homeland Security Committee were to be briefed Thursday on actions related to the no-fly list as well as other steps officials are taking to avoid a repeat of last week’s deadly violence. More than 100 people have been arrested in connection with the riots.