Volunteers and medical staff bring an injured man for treatment after two powerful explosions, which killed at least six people, outside the airport in Kabul on Aug 26, 2021. (WAKIL KOHSAR / AFP)

WASHINGTON - President Joe Biden, his voice breaking with emotion, vowed on Thursday the United States would hunt down those responsible for twin explosions at the Kabul airport in Afghanistan and said he had asked the Pentagon to develop plans to strike back at them.

Biden spoke hours after the blasts killed at least 13 American troops and scores of civilians, the worst day of casualties for US forces there in a decade.

Answering a reporter's question as to whether he'll deploy additional troops to Afghanistan in the wake of the attacks, Biden said if the military needs additional force, "I will grant it."

At least 28 members of the Taliban were among the people killed in explosions overnight outside the airport in Kabul, Afghanistan, a Taliban official told Reuters on Friday.

"We have lost more people than the Americans," said the official, who declined to be identified. 

Islamic State Khorasan (ISIS-K), an affiliate of militants who previously battled US forces in Syria and Iraq, claimed responsibility for the attack.

The Islamic State said one of its suicide bombers targeted "translators and collaborators with the American army". US officials also blamed the group.

"We will not forgive, we will not forget. We will hunt you down and make you pay," Biden said in remarks at the White House.

READ MORE: Afghan Taliban say expect foreign evacuations to end by deadline

He promised US evacuations would continue.

"We will not be deterred by terrorists, we will not let them stop our mission. We will continue the evacuations," he said.

The blast at the airport was followed by another one at the adjacent Baron Hotel, whose details are being figured out by the US military.

The Wall Street Journal, citing a senior Afghan health official, reported that the explosions left at least 90 Afghan civilians dead.

Satellite image shows Kabul International Airport and the location of an explosion near the Abbey Gate.

Answering a reporter's question as to whether he'll deploy additional troops to Afghanistan in the wake of the attacks, Biden said if the military needs additional force, "I will grant it."

Biden said he had ordered US military commanders to develop operational plans to strike ISIS-K assets, leadership, and facilities. "We will find ways of our choosing, without large military operations, to get them," he said.

The Islamic State said one of its suicide bombers targeted "translators and collaborators with the American army"

The president said he has thus far been shown no evidence of collusion between the Taliban and ISIS in masterminding both what happened in the morning and what was expected in the future. The Taliban issued a statement condemning the attacks in their aftermath.

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Close to the end of his White House appearance, Biden said he would "bear responsibility for fundamentally all that's happened" during the chaotic withdrawal in Afghanistan, while also shifting the blame on former president Donald Trump, whose administration negotiated a deal with the Taliban to get all US forces out of Afghanistan by May 1, 2021.

US President Joe Biden pauses as he speaks about the bombings at the Kabul airport that killed at least 12 US service members, from the East Room of the White House, Aug 26, 2021, in Washington. (EVAN VUCCI/AP)

The attacks came as the United States has been scrambling to evacuate Americans and its Afghan partners from Afghanistan since the Taliban entered Kabul on Aug 15.

The Taliban has said all US troops must leave Afghanistan no later than Aug 31, and Biden has upheld that deadline.

"The President relies on the advice of his military commanders and they continue to believe that it is essential to get out by the 31st (of August). That is their advice," White House Press Secretary Jen Psaki said at a press briefing following Biden's televised speech.  

Afghans lie on beds at a hospital after they were wounded in the deadly attacks outside the airport in Kabul, Afghanistan, Aug 26, 2021. (MOHAMMAD ASIF KHAN / AP)

Evacuation halted

Australia and Norway have stopped evacuation flights from Afghanistan after the suicide attacks.

Prime Minister Scott Morrison said Australia's military personnel had been evacuated from Kabul just hours before the attacks, and with security so precarious it was no longer safe to continue evacuations.

Prime Minister Scott Morrison said Australia's military personnel had been evacuated from Kabul just hours before the attacks, and with security so precarious it was no longer safe to continue evacuations

"Our plan now moves into its post evacuation stage and that involves ensuring the process of returning, through our official humanitarian program," Morrison told reporters in Canberra.

Morrison acknowledged some Australian visa holders remain in Afghanistan, though he said Canberra did not know exact numbers.

Norwegian Foreign Minister Ine Eriksen Soereide said on Thursday that Norway can no longer assist in evacuating remaining citizens from Afghanistan's capital.

"The doors at the airport are now closed and it is no longer possible to get people in," Soereide told broadcaster TV2.

Leaders from around the world have condemned the attack.

New Zealand's Prime Minister Jacinda Ardern said the attack was "despicable", adding the country's last evacuee flight had left prior to the explosions there.

"We strongly condemn what is a despicable attack on many innocent families and individuals who were simply seeking safety from the incredibly difficult and fragile situation in Afghanistan," Ardern said in a statement.

Canadian Prime Minister's Office said Prime Minister Justin Trudeau "strongly condemns terror attacks that took place earlier today near Hamid Karzai International Airport in Kabul."

Meanwhile, Spain has concluded its evacuation of personnel from Afghanistan and the last evacuees are expected to land at the Torrejon military airbase near Madrid later on Friday, the government said.

The United Kingdom said on Thursday it had evacuated more than 13,000 people from Afghanistan, with British Prime Minister Boris Johnson saying his government would continue with its evacuation operation in Kabul after an attack near the airport.