The United States has about 15,475 combat troops deployed to fight the war on terror, about 2,650 more troops than six months ago.

President Obama reported those troop levels Friday, saying the troops are authorized under a under a 2001 law giving the president the authority to use force against those responsible for the Sept. 11 terrorist attacks. Under the War Powers Resolution, the president must update Congress on the number of troops deployed to combat zones every six months.

Friday's report comes as Obama has renewed his call for Congress to pass a new law updating his authority to fight the Islamic State. "If Congress believes, as I do, that we are at war with ISIL, then it should vote to authorize the continued use of military force against these terrorists," he said Sunday in a televised address from the Oval Office.

The largest U.S. presence of combat troops is in Afghanistan, where Obama has abandoned his plans for a complete withdrawal by the time he leaves office. There are now 10,500 U.S. troops in Afghanistan, 1,400 more than there were in June.

Also, 3,550 troops remain in Iraq, and small teams are already in northern Syria to train and advise local opposition troops. The report says up to 50 new personnel "may be deployed in Syria as circumstances warrant."

The U.S. deployed 350 personnel to Turkey in July in order to support air strikes from Incerlik Air Force base, and added 375 more in November.

U.S. troops are also conducting counter-terrorism operations in the African nations of Niger (350 troops) and Cameroon (300 troops). Since June, the U.S. has also conducted counterterrorism operations in Somalia, Yemen, Djibouti and Libya. Obama also cites the 2001 law as authorization for U.S. involvement in Somalia, Yemen, Djibouti, Libya and Cuba.

Those numbers don't count another 3,700 combat troops deployed in hotspots like Jordan, Egypt, Kosovo and central Africa.