US Defence Secretary Lloyd Austin has made an unannounced visit to Afghanistan, weeks before a planned withdrawal of all remaining US troops. After meeting President Ashraf Ghani in Kabul, he called for a responsible end to the war but would not say whether the deadline would be met. Mr Austin said the focus should be on reducing high levels of violence to allow a negotiated end to the conflict. The pullout was agreed with the Taliban by the Trump administration last year. But there are questions over whether the insurgents have kept their pledge to negotiate with the Afghan government. New US President Joe Biden has said the 1 May deadline would be tough to meet, prompting warnings of "consequences" from the Taliban. Mr Austin is the first member of Mr Biden's cabinet to visit Afghanistan. He flew into Kabul on Sunday at the end of a brief tour of Asia. Speaking to journalists, Mr Austin would not say whether the Taliban had met their obligations under the recent deal. "It's obvious that the level of violence remains pretty high in the country," he said, quoted by the New York Times. "We'd really like to see that violence come down, and I think if it does come down it can begin to set the conditions for some really fruitful diplomatic work." There are fears that if foreign militaries withdraw before a lasting agreement is reached, the Taliban might return to power. The US says it has some 2,500 troops still in Afghanistan.