DUBAI - Militants attacked a Bahraini police bus near the Jidhafs area outside the capital Manama, killing one policeman and wounding eight others, the interior ministry said on Friday.

The attack targeted the bus on the Khalifa bin Salman highway, the ministry said, adding that the militant group used a handmade bomb.

“Investigations are underway to determine the circumstances of this premeditated terrorist attack and arrest the group involved,” the ministry said in a statement on its website.

The incident was the latest in a series of attacks targeting policemen in the country where the U.S. Fifth Fleet is based.

The government blames the attacks on Shia militants it says are backed by Iran to destabilise the country, a charge Tehran denies.

“A terrorist act targeted a police bus on Khalifa bin Salman highway” outside the capital Manama, the ministry said on its Twitter account.

“Several policemen injured. Relevant procedures are being taken,” the ministry said.

The statement provided no further details about the number of policemen injured, the type of attack or who was thought to have carried it out.

The blast happened near Jidhafs, a Shia town, witnesses said.