A US drone strike in Somalia is believed to have killed a senior member of the al-Shabab who allegedly helped plan the 2013 Westgate Mall attack in Nairobi, officials said.

Adan Garar and two others are suspected to have been killed in Thursday’s attack after their car was targeted near the town of Bardhere, the Kenyan and US officials said.

The senior Kenyan official, who insisted on anonymity because he was not authorised to give the information to the media, says Garar is also suspected of planning failed attacks on Kenya's coast and in the Ugandan capital, Kampala, last year. 

Both Kenya, Somalia's neighbour to the South, and Uganda have troops in the Horn of Africa nation battling al-Shabab, an armed group affiliated to al-Qaeda and is blamed for a spate of attacks in Somalia and in Kenya.

The US official also insisted on anonymity.

Anti-terror police foiled a planned attack in the coastal city of Mombasa after they intercepted a car packed with explosives in March 2014, according to Kenyan authorities.

According to police, al-Shabab fighters had planned simultaneous attacks on the international airport in Mombasa, the ferry crossing and a supermarket. The car laden with explosives was to be detonated on a ferry.

Al-Shabab has vowed to inflict violent attacks on Kenya and Uganda because the two countries have contributed troops to the African Union force supporting the government in Somalia.

Sixty-seven people were killed in the Westgate attack, which was carried out by four gunmen from al-Shabab.

Source: AP