Following the U.S. announcement, North Atlantic Treaty Organisation chief Jens Stoltenberg warned that a "hasty" withdrawal by the United States, which lead's NATO's coalition in Afghanistan, could lead to further violence.

As mortar shells slammed into a residential area of Afghanistan's capital, US Secretary of State Mike Pompeo has held what are likely his last meetings with Taliban and Afghan Government negotiators trying to negotiate peace. No group immediately claimed responsibility for Saturday's blasts.

"Met with both Taliban and Islamic Republic of Afghanistan's negotiating teams in Doha".

Saturday's barrage of rockets on Kabul comes amid a recent spike in battlefield violence between Afghan security forces and Taliban insurgents, which has killed countless combatants on both sides and civilians in November alone.

In an interview with local Al-Raya newspaper on the sidelines of his visit to Doha on Saturday, Pompeo said that he wanted very much to visit Doha during his current tour of the region to meet His Highness the Amir Sheikh Tamim bin Hamad al-Thani and HE the Deputy Prime Minister and Minister of Foreign Affairs Sheikh Mohamed bin Abdulrahman al-Thani.

Meanwhile, Abdullah Abdullah, head of the government's High Council for Reconciliation, condemned the attack in a tweet, calling it a "cowardly" act.

However, the Pentagon recently announced that Trump will reduce the number of U.S. forces from 4,500 to 2,500 before leaving office.

Trump has repeatedly vowed to end "forever wars", including in Afghanistan, America's longest-ever conflict, which began with an invasion to dislodge the Taliban following the September 11, 2001 attacks.

US President-elect Joe Biden also advocates winding down the war.

"We are exceptionally grateful that at a time of such collective suffering. your commitment to Afghanistan remains strong".

But senior diplomats told Reuters that a breakthrough was expected in the peace talks after the donor conference. The talks have made little progress so far.

"Whatever is possible, we will do to help reduce the violence", and help move the Afghan-Taliban talks toward a cease-fire, Khan said.

Under an earlier deal between the USA and the Taliban that outlined a gradual pullout, the remaining US forces were to leave Afghanistan by next April.

The Taliban are under pressure not to attack urban areas, having pledged not to do so under the terms of a United States withdrawal deal signed in February.

For most Afghans, the overriding concern for the peace talks has been a sharp rise in violence this year and a surge of attacks by the Taliban against Afghanistan's security forces since the start of negotiations in September.

It is unclear exactly what will happen to USA troop levels under President-elect Joe Biden, who is set to take office just days after the troop drawdown is set to begin.

Saturday's strike on the Afghan capital saw a barrage of rockets slam into various parts of central and north Kabul - including in and around the heavily fortified Green Zone that houses embassies and worldwide firms.

The rockets reportedly were fired from vehicles, hitting several densely populated areas.

While in Islamabad, Mr Abdullah urged Pakistan's powerful military to press the Taliban to reduce attacks and the level of violence.