WATCH: Biden has not spoken to any world leaders since fall of Kabul

Update: President Biden later spoke to UK PM Boris Johnson.

Reporters asked National Security Advisor Jake Sullivan on Monday if President Biden has spoken to other world leaders or allies since the falls of Kabul to the Taliban in Afghanistan over the weekend. The answer was a resounding no.

"He has not yet spoken with any other world leaders," Sullivan said. "Myself, Secretary Blinken, several other senior members of the team, have been engaged on a regular basis with foreign counterparts and we intend to do so in the coming days."

Sullivan said that his job, and the job of the others he mentioned, was one of coordination. "Right now the main issue is an operational issue," he said, "it's about how we coordinate with them to get their people out."

This comes as UK Prime Minister Boris Johnson spoke to German head Angela Merkel about convening an emergency meeting of the G7. It was reported that this call came after UK Foreign Secretary Dominic Raab stated that the fall of Kabul, and the takeover of Afghanistan by the Taliban, happened with much more speed than the UK and their allies had anticipated.

When asked why the president hasn't spoken to world leaders yet, White House Press Secretary Jen Psaki said that Sullivan had said that "our focus has been on operational efforts, which includes coordination at a lower level than leaders and heads of state."

"And that is our focus," Psaki said, "on working with third countries to get their citizens out or of course working with others on the ground to get vulnerable populations out. That's where the focus is at hand right now. And if there is a benefit in the president picking up the phone and calling a world leader he will certainly do that and I expect that he will do that in the coming days."

"Both leaders resolved to use their bilateral and multilateral influence to encourage international partners to adopt a joined-up approach to the challenges ahead," read a statement from 10 Downing Street after the phone call between Merkel and Johnson.

"The Prime Minister also stressed the need to agree shared international standards on human rights that any future Taliban government in Afghanistan will be held to by the international community. The Prime Minister outlined his intention to convene G7 leaders for a virtual meeting to discuss this at the earliest opportunity," the statement continued.

That Biden has not engaged in conversation with trusted allies in NATO was declared to be "indefensible" as well as a "dereliction of the office of the Presidency."

President Biden spoke from the East Room on Monday afternoon to address the situation in Afghanistan, saying that the national security team is working to "respond to every contingency, including the rapid collapse we're seeing now."

"I stand squarely behind my decision. After 20 years I've learned the hard way that there was never a good time to withdraw US forces. That's why we're still there. We were clear-eyed about the risks, we planned for every contingency," Biden said.

"But," he said, "I always promised the American people that I would be straight with you. The truth is: This did unfold more quickly that we had anticipated."

The US spent more than a trillion dollars during the near 20-year conflict, and the training of the Afghan military force, fully equipped with US military gear, was larger than the standing armies of many NATO allies, he said.