Police and security officials stand guard at a checkpoint on a highway in Sanabis west of Manama, Bahrain February 9, 2017. (Reuters photo)

MANAMA, Feb. 9 (Xinhua) -- Bahrain security forces killed three terror fugitives Thursday after intercepted their vessel, which was heading to Iran.

The vessel occupants fired shots at the security forces in a chase on the sea, said Public Security Chief Major-General Tariq al-Hassan, adding that they changed its route to the northern part of Bahrain and refused to stop despite warning by the Bahrain security forces.

The operation is one of the two which are taken as part of their investigations, he said, and three men were killed in the incident, including one who was among 10 escaped men from the Jaw prison facility.

The men named Redha al-Ghasra, who was sentenced for life and additional 79 years for several terror cases, escaped for the fourth time from detention.

Maj. Al Hassan said a group of 10 terror fugitives were trying to escape in the boat and during the clashes two sustained injuries and five were arrested.

"We found a satellite phone, GPS system, money and personal belongings from the boat," he said.

"Preliminary investigations indicate that some groups in Iran were waiting to escort this boat," he added.

The second operation arrested two men with cache of weapons which included main suspect involved in the killing of a policeman last month.

The official revealed that 18 policemen were killed since the 2011 unrest and more than 3,200 injured in terror attacks.