Gunmen stormed into a Tamil-language newspaper office in northern Sri Lanka and opened fire, killing two employees and seriously wounding a third, the editor said.

"Some men dressed in black broke into our office and opened fire," said N. Vithyatharan, editor of the Uthayan newspaper based in the northern town of Jaffna, 300 kilometers (185 miles) north of Colombo.

He said the newspaper's editorial manager and a circulation assistant died, and another employee was wounded in the Tuesday attack.

"They were looking for three of our reporters, but they managed to escape because our office is large," Vithyatharan said.

Uthayan is an independent newspaper, but is considered to have close links to Tamil Tiger rebels fighting for a separate homeland for the country's ethnic Tamil minority.

"I have no doubts that this is a work of armed groups working with the government security forces," Vithyatharan said, adding that the reason for the attack may have been a cartoon the newspaper published on Monday of the leader of rival group showing him prostrating himself before the president.

Tamil Tiger rebels accuse the government of using other armed Tamil groups to attack the guerrillas. The groups, which once fought alongside the Tigers for a separate state, gave up their struggle after a failed India-arranged peace accord in 1987.

The government has denied backing such groups.

President Mahinda Rajapakse, scheduled to address an international media freedom conference in Colombo on Wednesday, phoned the newspaper publisher and denied any government involvement in the attack, Vithyatharan said.

"His thinking was that the Tigers had done it ahead of his speech to embarrass him. But we clearly told him that the government should bear the responsibility," Vithyatharan said.

Liberation Tigers of Tamil Eelam rebels have fought the government since 1983 to create a separate nation for ethnic minority Tamils, accusing the majority Sinhalese-dominated state of discrimination.

More than 65,000 people were killed in the conflict before a Norway-brokered cease-fire was signed in 2002.

Peace talks later broke down, and the truce itself has been seriously undermined by growing violence.

In the past month, more than 150 people have died in shootings and bomb explosions which the government blames on the rebels.

The rebels, however, deny responsibility and accuse government forces and pro-government groups of targeting the rebels.