Story highlights Ashton Carter: Obama considering "possible changes" to U.S. troop drawdown timeline

Carter will visit U.S. troops and Afghan officials during his two-day stay in Afghanistan

(CNN) President Barack Obama may change the United States' plan to withdraw virtually all its troops from Afghanistan by the end of 2016, his new defense secretary said Saturday during a visit to the central Asian nation -- an indication that the White House is considering extending the U.S. troop presence there beyond that year.

U.S. Defense Secretary Ashton Carter made the comment in a news conference in Kabul with Afghan President Ashraf Ghani, who has previously called on Obama to "re-examine" the withdrawal plan to ensure his country has the support it needs to maintain security gains.

Carter arrived in Afghanistan's capital on Saturday during his first foreign trip since being sworn in as defense secretary four days ago.

"Our priority now is to make sure this progress sticks. That is why President Obama is considering a number of options to reinforce our support for President Ghani's security strategy, including possible changes to the time line for our drawdown of U.S. troops," Carter said.

"That could mean taking another look at the timing and sequencing of base closures to ensure we have the right array of coalition capabilities to support our Afghan partners," he said.