Two men have been arrested driving a vehicle packed with explosives in the Kenyan coastal city of Mombasa, police said.
The men were arrested on Monday with two homemade bombs and a mobile phone, which could have been used as a detonator.
"We have not established where the target was, but we have detained two terror suspects who were in the vehicle," Henry Ondiek of the Mombasa Criminal Investigation Department told the AFP news agency.
"We were tipped off that the two were headed for an attack on an unspecified place and we laid an ambush and got them," Ondiek said.
Another police source, requesting anonymity, said the two men were of Somali origin.
Kenya has suffered a string of attacks blamed on the al-Shabab armed group based in Somalia, including the September 2013 attack in Nairobi's Westgate mall in which at least 67 people were killed.
Kenya's top security chiefs have warned of "increased threats of radicalisation" from home-grown groups, singling out Mombasa's Musa mosque as a specific centre encouraging what they call extremism.
Intelligence officials had previously raided the mosque and accused officials of recruiting fighters for al-Shabab.