WASHINGTON (Reuters) - President Donald Trump’s new Pentagon team has not yet signalled an imminent withdrawal of all U.S. troops from Afghanistan, raising expectations among U.S. officials and allies that Trump might settle for a partial reduction before leaving office.A U.S. official, speaking on condition of anonymity, said the military was expecting formal orders in the coming days to go down to about 2,500 troops in Afghanistan by early next year from around 4,500 currently. A NATO official also cited expectations of a 1,500 to 2,000 troop decline. Trump fired his defense secretary, Mark Esper, and appointed other top Pentagon officials last week after longstanding concerns that his priorities were not being dealt with urgently enough at the Defense Department. They included ending the 19-year-old Afghan engagement by Christmas, an ambitious target that opponents of the country’s longest war welcomed but which Trump’s critics warned could be reckless given ongoing militant violence plaguing Afghanistan. Afghanistan has featured in a flurry of introductory calls by acting Defense Secretary Christopher Miller, Esper’s replacement, to U.S. allies’ defense ministers and chiefs of defense, a senior U.S. defense official told Reuters. “It was a part of many of them because it is of great importance to our NATO allies, our allies in the region and also just global security and protecting the American homeland,” the official said, speaking on condition of anonymity. But the official, speaking after the calls with allies, suggested that Trump would not push a withdrawal faster than conditions on the ground allow. U.S. and Afghan officials are warning of troubling levels of violence by Taliban insurgents and persistent Taliban links to al Qaeda. It was those ties that triggered U.S. military intervention in 2001 following the 9/11 attacks, which al Qaeda carried out. Thousands of American and allied troops have died in fighting in Afghanistan since then. Some U.S. military officials, citing U.S. counter-terrorism priorities in Afghanistan, have privately urged Trump against going to zero at this point and want to keep U.S. troop levels at around 4,500 for now. “The president has acted appropriately in this, has never said: ‘Hey, we’re going to zero. Let’s go tomorrow.’ It has always been a conditions-based effort and that effort continues,” the senior U.S. defense official said, without explicitly detailing future drawdown plans. The White House did not immediately respond to a request for comment.Over the past four years, predicting Trump’s policy pronouncements has not always been easy. On Oct. 7, Trump said on Twitter here "We should have the small remaining number of our BRAVE Men and Women serving in Afghanistan home by Christmas!" But U.S. officials say he has yet to issue orders to carry that withdrawal out. On Monday the first U.S. official said the Pentagon had told commanders to start planning for the more moderate reduction to 2,500 troops. A total withdrawal now would be difficult for the U.S. military to execute, especially given the reliance of NATO allies on the United States for logistical support, they add.