COLOMBO -- Sri Lanka has invited Scandinavian truce monitors to travel in navy gun boats patrolling the island's northeast to prevent rebel gun running, Prime Minister Ranil Wickremesinghe said Sunday.

Peace broker Norway was told that foreign monitors could have unrestricted access to naval craft to ensure there was no violation of the bilateral truce that went into effect Saturday, the prime minister said.

He said the monitors drawn from Norway, Sweden, Denmark and Finland were expected to be here in the next few days with the head of the monitoring panel expected by Monday.

Smuggling of arms and other supplies by the rebel Liberation Tigers of Tamil Eelam (LTTE) along the island's northeastern sea board where the rebels have a strong hold had been a sensitive issue, AFP reported.

Navy gun boats and a flotilla of rebel boats clashed in high seas on Thursday, the day the government gave its assent to the truce deal which was approved by LTTE supremo Velupillai Prabhakaran a day earlier.

The truce is due to be fully implemented over a period of 90 days.

Under the deal, both LTTE members and government forces will have access to each other's areas as long as they are unarmed and out of uniform.

Tamil paramilitary groups which are currently co-operating with government forces are to be disarmed within 30 days and the security forces are to offer to integrate them with the regular military.

Both sides will be prevented from firing weapons or carrying out ambushes, armed raids, assassinations, abductions, extortion and the destruction of civilian and military property.

However, government forces can continue their legitimate tasks of safeguarding the sovereignty and territorial integrity of Sri Lanka without engaging in offensive operations against the LTTE.

The Prime Minister warned there could be setbacks in implementing the truce agreement, but the foreign monitoring would help minimize difficulties.

"We have to now implement the agreement and there will be difficulties, I won't say it will be all plain sailing," Wickremesinghe said, adding that he wanted to address the humanitarian issues before starting substantive talks.

"The real problems will arise then," he said.

He added that the government was offering devolution of power to ensure that all Sri Lankans were treated equally.

"Our idea of devolution may not the same as that of the LTTE, but we can discuss these things at the table."

The Marxist JVP, or the People's Liberation Front which has 16 seats in the 225-member Parliament, described the truce deal as a "document of surrender."

"It is crystal clear that Ranil Wickremesinghe's regime will make any mean betrayal to console the Tigers, and that Norway delegates are not facilitators but Tiger pets," the JVP said in a statement.

The JVP, which led two unsuccessful attempts to overthrow governments in 1971 and 1987 leaving some 80,000 people dead, demanded that the Norwegians be kicked out of the country.