Nairobi, March 24 (IANS): Security forces have intensified round the clock surveillance and foiled terror threats to ensure that the country is safe despite Sunday's terror attack in Mombasa, Kenyan police chief said Sunday.

The police have launched investigations to establish the motive behind the killing of four worshipers in the coastal city of Mombasa which also left some 17 injured, Xinhua quoted police inspector general David Kimaiyo.

"We have launched the investigations of what could be the motive behind the heinous act. Police are currently pursuing the attackers," the police chief said in a statement issued in Nairobi late Sunday.

"The police have been on high alert and we have been conducting intensive patrols and gathering information all over the country."

Kimaiyo's remarks come after four worshipers were shot dead earlier in a terror attack. Three minors were among those in critical conditions amid fears that the toll may rise because some of them had life threatening injuries.

Kimaiyo said the church attack was carried out by two unidentified gunmen armed with AK-47 rifles who sprayed bullets randomly at worshippers at Kings Joyland church in Likoni, south of Mombasa.