Two blasts killed at least 85 people including 13 US soldiers near the airport on Thursday, ripping through crowds desperate to flee Taliban-controlled Afghanistan.

The Islamic State group said it carried out the attacks.

The blasts show "the security situation in Afghanistan is still complex and severe", Chinese foreign ministry spokesman Zhao Lijian told reporters on Friday.

"China is shocked by and strongly condemns the explosions," Zhao said, adding that the ministry had not received any reports of Chinese casualties.

More than 100,000 people have been evacuated from Afghanistan since the Taliban swept to power on August 15, with many Afghans desperate to escape the feared hardline rule of the Islamists.

The Taliban have allowed US-led forces to conduct the airlift while they finalise plans for a government to be announced after the American troops leave.

But Islamic State jihadists, rivals of the Taliban with a record of barbaric attacks in Afghanistan, were intent on capitalising on the chaos in Kabul.

Zhao on Friday said China "hopes the relevant parties can take effective measures to ensure a smooth transition of the situation".

Beijing has said it is ready to deepen "friendly and cooperative" relations with Afghanistan after the Taliban seized power in a lightning offensive amid the chaotic pullout of American troops.

There is a potential resource boom to be had from Afghanistan's vast copper and lithium mines but experts say the perilous security situation means any immediate commodities rush by Chinese firms is unlikely.

China, which shares a 76-kilometre (47-mile) border with Afghanistan, is wary that its neighbour could become a staging ground for Muslim-minority Uyghur separatists looking to infiltrate the sensitive border region of Xinjiang.