NAIROBI, Kenya — Kenyan police disrupted a major terrorist attack Friday in its final stages of planning, arresting two people with explosive devices and seizing a cache of weapons and ammunition, officials said.

A manhunt has been launched for eight more suspects including would-be bombers and the masterminds behind the planned attack, police spokesman Eric Kiraithe said.

The pair was arrested in an area of Nairobi where many Somali immigrants live, said Boniface Mwaniki , the head of Kenya's Anti-Terrorism Police Unit. He said the men are suspected of having links with al-Shabab, an al-Qaida-linked militant group in neighboring Somalia.

Police found four suicide vests rigged with hundreds of metal ball bearings, two improvised explosive devices, also rigged with ball bearings, four AK-47 assault rifles, ammunition and 12 grenades, he said, adding that the vests are similar to that one used in attacks in Uganda on crowds watching the soccer World Cup final on TV in July 2010, killing 76 people, Mwaniki said.

Kiraithe identified the two suspects in custody as Abdul Majid Yassin Mohammed, 26, a Kenyan of Somalia origin, and Suleiman Abdi Aden from Somalia.