Two senior commanders with the American-backed Free Syrian Army were kidnapped and executed by al Qaeda fighters, highlighting the increasingly violent schism between the country's secular opposition and the Islamic radical groups fighting alongside them.
The attack was the first American drone strike against members of the Yemeni faction since a deadly suicide bombing in the country's capitol of Sanaa Thursday.
Al Qaeda leaders claimed responsibility for the attack, which targeted Yemen's Defense Ministry.
The casualties were the first suffered by French troops since Paris deployed those forces onto the continent last week.
There are more than 1,000 French troops on the ground, as part of a joint French-African Union-led peacekeeping force.
Tuesday's casualties came a day after the Pentagon announced plans to provide military support to that joint force.
Defense Secretary Chuck Hagel is directing the military to transport troops from Burundi to the Central African Republic.
The defense secretary arrived despite tensions with the U.S.-backed Afghan regime.
The statement marks another milestone in the effort to remove Bashar Assad’s stockpiles.
The Obama administration still refuses to acknowledge the validity of the zone, which sits over the Senkaku islands, known as Diaoyu in China, in the East China Sea.
That said, Vice President Biden pressed Chinese President Xi Jinping, to ease the identification and notification requirements for military and civilian aircraft traveling through the contested area.
The Pentagon has ordered all American forces stationed in the Mideast are on high alert in the wake of Thursday's bombing in Yemen.
"The United States military has increased its regional alert status following the terrorist attack on the Yemeni Republic Ministry of Defense," according to a department statement issued Friday.
U.S. forces are standing at the ready to provide support for French and African troops battling rebel forces in the Central African Republic, according to the Pentagon's top military officer.
"We're in contact with our French counterparts" regarding the ongoing operation in Africa, Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey said Wednesday.