A suspected U.S. drone strike in western Yemen killed at least five people on Monday in the first such attack since Yemen’s army launched an offensive against Al-Qaeda-linked fighters last month.

The pilotless aircraft targeted a vehicle carrying suspected members of Al-Qaeda in the village of Al-Husun, Marib province, military and security officials said. Authorities were checking for the identities of the slain targets.

The United States is the only country operating drones over Yemen, but U.S. officials rarely acknowledge the covert drone program.

Monday’s strike comes after a series of deadly attacks over the weekend in the capital Sanaa and elsewhere in the country’s south.

On Sunday, a suicide bomber rammed an explosives-laden car into a military police base in Al-Mukalla, in southeast Yemen, killing at least 11 people. Earlier in the day, three Al-Qaeda fighters were killed as they tried to attack a security checkpoint close to the presidential palace in Sanaa.

Yemen's army launched a major offensive on April 29 against strongholds of Al-Qaeda in the Arabian Peninsula (AQAP) in three southern and eastern provinces. Yemeni officials say they have inflicted heavy losses on the fighters.

The offensive was preceded by a wave of U.S. drone strikes that killed scores of suspected Al-Qaeda fighters last month in southern and central regions. The U.S., which also trains Yemen’s counterterrorism forces, has launched more than 110 strikes since 2002, according to the New America Foundation.

Civilian casualties from these strikes, however, have sparked international outrage.

AQAP has been linked to a number of failed plots against the U.S., and its leader Nasser al-Wuhayshi recently appeared in a rare video in which he vowed to attack Western "crusaders" wherever they are.

Al-Qaeda uses the term “crusaders” to refer to Western powers, especially those they consider predominantly Christian — such as Britain, France and the U.S. — that have intervened militarily in Muslim countries.

The U.S. considers AQAP to be the most dangerous branch of Al-Qaeda in the world.

Al Jazeera and wire services