LONDON, Aug 16 (Reuters) - British Prime Minister Boris Johnson intends to host a virtual meeting of G7 leaders to tackle the deteriorating situation in Afghanistan and has stepped up efforts to evacuate UK nationals and others from Kabul. Johnson spoke to French President Emmanuel Macron on Monday to agree how the two countries could work together to recognise any future Afghan government and in trying to prevent a humanitarian and refugee crisis, his office said. The G7 call is expected to happen in coming days, while the two leaders also agreed that their countries should work together at the U.N. Security Council, including on a possible joint resolution. British Foreign Secretary Dominic Raab said Western partners would also look at imposing sanctions and withholding aid if the Taliban failed to uphold human rights or allowed the country to become a base for terrorism again. "It is not what we wanted," Raab said. "But we have to deal with a new reality, we"re making it clear with our partners, with all the means at our disposal, that we will hold the Taliban to account to its commitments to have a new start in Afghanistan." Western governments are discussing how to handle the situation in Kabul where thousands of civilians desperate to flee Afghanistan have descended on the airport after the Taliban seized control of the country. read more Raab said everyone had been surprised by the scale and speed of the takeover and British troops were now working to bring home British nationals and those Afghan citizens who had worked for the British army there. London had initially committed 600 soldiers to help the evacuation but that has now been increased to 900 in Kabul. Further personnel would be deployed in the region and be able to move to Afghanistan quickly if needed, the Ministry of Defence said. Personnel will also be ready to deploy at short notice from Britain if required for defensive duties. Reporting by Kate Holton and William James. Editing by Jane Merriman and Nick Macfie Our Standards: The Thomson Reuters Trust Principles.