Islamic State claimed responsibility for a deadly attack in Uganda's capital Kampala on Tuesday after three suicide bombers killed six people, the group said on social media.

Six people, including three suicide bombers, were killed and 33 others injured, police said.

The attacks came within three minutes of each other. More bombs have been found in other parts of the city, officials said.

A fourth attacker has been arrested, and an explosive vest recovered, police said.

(With input from agencies)