U.S. military and intelligence agencies are heavily involved in joint operations with Yemeni troops that have killed six of 15 top leaders of Al Qaeda in the Arabian Peninsula since mid-December.

The operations, approved by President Obama, involve several dozen troops from the U.S. military's Joint Special Operations Command (JSOC), which focuses on killing or capturing suspected terrorists. Although the American advisers do not participate in raids inside Yemen, they provide weapons and munitions, provide weapons and munitions and help develop tactics.

"Highly sensitive intelligence is being shared with the Yemeni forces, including electronic and video surveillance, as well as three-dimensional terrain maps and detailed analysis of the al-Qaeda network," the Washington Post reported Wednesday.

The operations included a December 24 airstrike that targeted Anwar Al-Awlaki, who military officials said is on a shortlist of American citizens the JSOC seeks to kill or capture. Awlaki told Al Jazeerah that he gave Nidal Malik Hasan his blessing to carry out the Fort Hood massacre November 5. Awlaki also had direct contact with Umar Farouk Abdulmutallab, who attempted to carry out a suicide attack on a trans-Atlantic flight Christmas Day.

There are questions about how vigorous the U.S. government has been in its efforts to target Awlaki. The Investigative Project on Terrorism reported that some U.S. intelligence officials believe they could have used a Predator drone strike to kill Awlaki but held back because he is an American.