Kenyan police say they have arrested two people suspected to have links with an Al Qaeda-linked Somali militant group that was in the last stages of planning a major terrorist attack on Kenyan soil.

Boniface Mwaniki , the head of Kenya's Anti-Terrorism Police Unit, said Friday that police found four suicide vests, a cache of weapons and 12 grenades.

Kenya has suffered grenade attacks that have killed more than 50 people. Police have attributed them to sympathizers of the al-Shabab militant group in Kenya.

Al-Shabab has vowed to carry out terror attacks in Kenya in retaliation against the country for sending troops into Somalia to hunt the militants it blames for a series of cross border attacks, including the kidnapping of four Europeans last year.