LONDON, Aug 22 (Reuters) - Britain plans to push world leaders to consider new sanctions on the Taliban when the G7 group of advanced economies meet on Tuesday to discuss the crisis in Afghanistan, sources told Reuters. British Prime Minister Boris Johnson, who currently leads the group that includes the United States, Italy, France, Germany, Japan and Canada, called on Sunday for the virtual meeting, in the wake of the Taliban"s swift takeover of Afghanistan. Britain believes the G7 should consider economic sanctions and withhold aid if the Taliban commits human rights abuses and allows its territory to be used as a haven for militants, according to a British government official, who spoke on condition of anonymity, and a second Western diplomat. U.S. President Joe Biden told reporters on Sunday that the Taliban had not taken any action against U.S. forces controlling Kabul airport, and had largely followed through on their pledge to let Americans reach the airport safely. Asked whether he would support Britain"s push for sanctions if the Taliban committed abuses, Biden said, "The answer is yes. It depends on the conduct." Taliban militants seized control of Kabul last weekend in an upheaval that sent civilians and Afghan military allies fleeing for safety. Many fear a return to the austere interpretation of Islamic law imposed during the previous Taliban rule that ended 20 years ago. "It is vital that the international community works together to ensure safe evacuations, prevent a humanitarian crisis and support the Afghan people to secure the gains of the last 20 years," Johnson said on Twitter on Sunday. Sanctions against the Taliban are unlikely to be adopted immediately, one Western diplomat said. British Foreign Secretary Dominic Raab first raised the possibility of sanctions to pressure the Taliban last week. read more Biden, under fire at home and abroad for his handling of the withdrawal of U.S. forces from Afghanistan, last week said G7 leaders would work out a joint approach to the Taliban, and has already held bilateral talks with Johnson, German Chancellor Angela Merkel, French President Emmanuel Macron and Italian Prime Minister Mario Draghi. Johnson plans to push Biden to extend his Aug. 31 deadline for withdrawing U.S. forces from Afghanistan so that more people can be evacuated, British media reported. On Sunday, Biden said the U.S. military was discussing potentially extending the deadline, but hoped that would not be necessary. He said Washington would consider an extension if asked to do so by G7 allies, but was working closely with those countries and others to help evacuate their citizens. The U.S. military earlier on Sunday said it had ordered commercial aircraft to help transport people who have already been evacuated from Afghanistan. Biden told reporters on Friday that he and U.S. Secretary of State Antony Blinken would work with other countries to set "harsh conditions" for any cooperation with or recognition of the Taliban, based on their treatment of women and girls and overall human rights record.