US military personnel are engaged in counterterrorism operations across 15 different countries, President Barack Obama said in a biannual statement to Congress released on Monday.

The letter outlined US military counterrorism operations across the globe in Afghanistan, Iraq, Syria, Turkey, Somalia, Yemen, Djibouti, Libya, Cuba, Niger, Cameroon, the Central African Republic, Egypt, Jordan, and Kosovo. All nations have US combat-equipped personnel deployed for a specific counterterrorism mission.

Obama indicated that that there is no timeline for the war on terrorism, and he will direct “additional measures to protect US citizens and interests” if necessary.

“It is not possible to know at this time the precise scope or the duration of the deployments of US Armed Forces necessary to counter terrorist threats to the United States,” Obama said.

Under the 2001 authorization for use of military force, the US president must update Congress every six months on the military operations against al-Qaeda, the Taliban and associated forces.