A small bomb exploded in the parking lot of a highway patrol station in eastern Saudi Arabia, injuring a policeman, state media said on Friday. The attack happened late Thursday in Al-Ahsa governorate, the Saudi Press Agency said, citing a provincial police spokesman. One member of the police force received a minor injury and five vehicles were slightly damaged, the spokesman said. "Authorities started criminal investigations," he added. Prince Saud Bin Naif, emir of the Eastern Province, was reassured on the health condition of the policeman. The prince expressed hope that the security authorities would soon catch the culprits and bring them to justice. "Those who have carried out these terror attacks are accustomed to killing innocent people and have resorted to violence on the orders of terrorists from outside the Kingdom," Prince Saud said. He congratulated the security forces for foiling attempts to carry out terror attacks with the evil design of undermining the security of the Kingdom. He also praised the citizens and expatriates for cooperating with the security authorities to arrest the terrorists and for denying them any kind of help.