Two officers were wounded, one critically, when a police intelligence patrol was ambushed in east Lebanon as it hunted people wanted over the kidnapping of seven Estonians, an official said on Saturday.

"Two of our cars on patrol came under fire while crossing the bridge that connects Chtaura to Jalala as police intelligence were planning an operation to crack down on the network we believe is responsible for the kidnapping in March of seven Estonians," who have since been freed, a police spokesman said.

He added that two officers were wounded, one of whom was in a critical condition, when masked gunmen opened fire on the patrol from a vehicle that had been reported stolen hours earlier. No arrests have yet been made.

The ambush also came a day after a shootout between police and suspected members of the network involved in the kidnapping.

Seven Estonian cyclists were freed in Lebanon in July, almost four months after armed men abducted them as they entered the country on a bicycle tour from neighbouring Syria. The abduction has not been officially claimed.

The police spokesman said on Saturday that members of the network were still active in Lebanon and posed a threat to security.

"It is possible there could be more kidnappings as several members of the network are still on the loose, although we have made a string of arrests," he added.

"They still pose a threat to our country and security."

Lebanon's Bekaa Valley is notorious for lawlessness, drug trafficking and feuding tribal clans, and patrols by security forces have regularly come under attack there.