Covert US drone attacks on Yemen have increased this month to exceed the number of strikes on Pakistan's tribal areas, a Bureau of Investigative Journalism reports states.

Up to 500 people, many of whom were civilians, have been killed since last May as part of the US drive to eliminate al-Qaeda from the Arabian Peninsula, according to the report.

But, even after attacks with civilian casualties, there has been little reaction from the Yemeni government.

Al Jazeera's Nadim Baba reports.