UK likely to follow US Afghanistan troop withdrawal: minister
Wallace said that while the UK will continue to work with Washington Kabul regarding Afghanistan's security, it will also reduce its troop numbers.
"I expect if they (the US) are reducing at some stage, we will come down," Wallace was quoted by Reuters as saying.
Wallace's remarks follow the Pentagon's announcement on Tuesday that the US will cut down its troop numbers in Afghanistan from 4,500 to 2,500 by mid-January.
In October, US President Donald Trump shocked senior Pentagon officials by suggesting that he would try to bring all US troops home from the country by Christmas.
"Part of this defence review is how can Britain be more independent," Wallace told Sky News.
"How can we complement each other around the world. If one power or another pulls out and we... decide we want to stay longer, we could do so."
"At the moment if the United States unilaterally pulls out of some of these countries we have a challenge."