UK Prime Minister Boris Johnson on Monday said he intended to host an online G7 meeting this week to discuss recognising any future Afghan government and preventing a humanitarian and refugee crisis in Afghanistan.
In a call with French President Emmanuel Macron, Mr Johnson said the international community had to take a unified approach on Afghanistan.
The two said it was vital to work together on the long-term future of Afghanistan and help nationals of both countries, and others, move to safety.
The leaders agreed that the UK and France should work together at the UN Security Council, including on a possible joint resolution.
Meanwhile, UK Foreign Secretary Dominic Raab said the international community was “surprised” by the speed of the Taliban victory.
Mr Raab said Britain would use all the means at its disposal to hold the Taliban to account in Afghanistan.
He suggested the UK could reduce aid to Afghanistan, introduce new sanctions or keep current penalties in place, depending “on the behaviour of the Taliban”.
In a televised speech, Mr Macron promised on Monday that France would not abandon Afghans who worked for his country, including translators and kitchen staff, as well as artists, activists and others under threat from the Taliban.
He said that protecting those who helped France over the years was an “absolute urgency", and that two military planes carrying special forces were due to arrive in Kabul “in the coming hours".
The exact timing was not immediately clear because the US temporarily shut down the Kabul airport to civilian and military flights after chaos on the tarmac that left at least seven people dead.
The aircraft would fly from a base in Abu Dhabi, a transit stop for those whom France is flying out.
Mr Macron said in his recorded speech that it was not known how many would be involved in the evacuation.
France has already pulled out about 1,400 Afghan employees and families, and moved citizens on a charter flight in July.
Paris withdrew all of its soldiers from Afghanistan after 13 years by December 2014, but continued to work with civil society.
Mr Macron pledged that the fight against “terrorism in all its forms” would not end.
“Afghanistan cannot again become the sanctuary for terrorism that it was,” he said.
Stability can only come about through political and diplomatic actions to be defined in the days ahead with the UN Security Council, Mr Macron said.
“We will do everything so that Russia, the United States and Europe can co-operate efficiently because our interests are the same,” he said.
Mr Macron said France, Germany and other European countries would work swiftly on developing a “robust response” to another major concern for many countries: an influx of migration by Afghans.
He said Afghanistan, “will also need in the times ahead its (people) and Europe cannot alone assume the consequences of the current situation".
Germany's Chancellor Angela Merkel said the US-led Nato operation in Afghanistan had achieved less than planned.
Mrs Merkel said she shared the pain of families of soldiers who died there “as it seems right now like it was all in vain".
The mission stopped Al Qaeda repeating its September 11, 2001 attacks on the US, but “everything else that has followed has not been as successful and has not been achieved in the way that we had planned”, she said.
The rapid return of the Taliban to power was “particularly dramatic and terrible”, Mrs Merkel said.
“It is terrible for the millions of Afghans who had worked for a freer society and who, with the support of the western community, have focused on democracy, on education, on women's rights,” she said.
It was also devastating for the loved ones of soldiers who paid with their lives in the Nato operation, Mrs Merkel said.
Lessons must be drawn from the two-decade operation, she said: “You also have to set smaller goals, I think, in such missions."
Germany and other western countries should provide aid to countries bordering Afghanistan to help them deal with Afghans fleeing the Taliban or risk a repeat of the 2015 migrant crisis, she said.
“We need to make sure that the many people who have big worries and concerns, even though they have not worked with German institutions, have a secure stay in countries neighbouring Afghanistan.
“We should not repeat the mistake of the past when we did not give enough funds to UNHCR and other aid programmes, and people left Jordan and Lebanon towards Europe.”
The leader of Mrs Merkel's CDU party, Armin Laschet, had earlier on Monday called the Afghanistan operation the “biggest debacle” in the alliance's history.