WASHINGTON (AP) - The United States has the capacity to evacuate the approximately 300 U.S. citizens remaining in Afghanistan who want to leave before President Joe Biden’s Tuesday deadline, senior administration officials said, as rocket fire in Kabul and another U.S. drone strike against suspected Islamic State militants underscored the grave threat in the war’s final days.

“This is the most dangerous time in an already extraordinarily dangerous mission these last couple of days,” America’s top diplomat, Secretary of State Antony Blinken, said Sunday not long before confirmation of the drone strike in Kabul.

The steady stream of U.S. military jets taking off and landing at Hamid Karzai International Airport in Afghanistan’s capital continued Monday even after rocket fire targeted the airport. No one claimed responsibility for the rockets, which hit a nearby neighborhood. U.S. Central Command spokesman Bill Urban said five rockets targeted the airport and a U.S. defensive system on the airfield known as a Counter Rocket, Artillery and Mortar System, or C-RAM, was employed against them. He said there were no U.S. casualties and the airfield continued to operate. Further details were not immediately available. The White House said President Joe Biden had been briefed on the rocket attack.

Biden’s national security adviser, Jake Sullivan, said Sunday that for those U.S. citizens seeking immediately to leave Afghanistan by the looming deadline, “we have the capacity to have 300 Americans, which is roughly the number we think are remaining, come to the airport and get on planes in the time that is remaining.”

Sullivan said the U.S. does not currently plan to have an ongoing embassy presence after the final U.S. troop withdrawal. But he pledged the U.S. “will make sure there is safe passage for any American citizen, any legal permanent resident” after Tuesday, as well as for “those Afghans who helped us.” But untold numbers of vulnerable Afghans, fearful of a return to the brutality of pre-2001 Taliban rule, are likely to be left behind.

Blinken said the U.S. was working with other countries in the region to either keep the Kabul airport open after Tuesday or to reopen it “in a timely fashion.”

He also said that while the airport is critical, “there are other ways to leave Afghanistan, including by road and many countries border Afghanistan.” The U.S., he said, is “making sure that we have in place all of the necessary tools and means to facilitate the travel for those who seek to leave Afghanistan” after Tuesday.

There also are roughly 280 others who have said they are Americans but who have told the State Department they plan to remain in the country or are still undecided. According to the latest totals, about 114,000 people have been evacuated since the Taliban takeover Aug. 14, including approximately 2,900 on military and coalition flights during the 24 hours ending at 3 a.m. Sunday.