WASHINGTON — A small number of U.S. special operations forces will be deployed to northern Syria to work with local ground forces in the fight against Islamic State militants, senior U.S. officials said Friday, marking the first time American troops will be working openly on the ground in the war-torn country.

U.S. officials said President Barack Obama ordered the deployment of fewer than 50 commandos to help coalition forces coordinate with the local troops.

Although the number is small, it marks an escalation of U.S. involvement in the fight against the Islamic State, which controls a large part of northern Syria and has its self-proclaimed capital in the Syrian city of Raqqa.

One official said that a first group of forces — possibly a couple of dozen — will go relatively soon to assess the situation and determine which groups on the ground the U.S. can best work with. More special operations forces would follow once the U.S. better determines what the needs are.

Defense Secretary Ash Carter hinted at the deployment earlier this week, saying the U.S. was retooling its strategy in Iraq and Syria and would conduct unilateral ground raids if needed to target Islamic State militants. The U.S. has done special operations raids in Syria, and it participated in a ground operation to rescue hostages last week in northern Iraq that resulted in the first U.S. combat death in that country since 2011.

The U.S. will also be sending additional aircraft, including F-15 fighters and A-10s to the Incirlik air base in Turkey, likely repositioning them from other spots in the region.

The officials were not authorized to discuss the matter publicly so spoke on condition of anonymity.