The slain editor of a prominent Sri Lankan newspaper, known for its vocal anti-establishment stand on the war on the Liberation Tigers of Tamil Eelam, was buried in Colombo on Monday as the government came under heavy flak, including from a senior ruling party leader, for failing to stop attacks on the media.

Former president and ruling Sri Lanka [Images] Freedom Party leader Chandrika Kumaratunga joined the growing number of opposition politicians and media watchdogs in questioning the government's performance in protecting media freedom.

Nearly 5,000 people, many wearing black armbands and chanting anti-government slogans, took part in the funeral procession for Wickramatunga. Some protestors also burned an effigy of President Mahinda Rajapaksa.

"If the LTTE [Images] can be tackled, why can't they (the government) tackle attack on the media. It is the responsibility of the government to prevent attacks on the media," Kumaratunga said after paying her respects to the body of the editor of The Sunday Leader, Lasantha Wickramatunga, at his house.

Coming out against the government, she said "what is even more dangerous and frightening is that this is not the first time that the journalists have been threatened, killed or intimidated. Even democratic opponents, political opponents have been threatened. This has gone on for the last three years."

Wickramatunga, known to have strong views against the government, was shot dead at a busy place in the heart of Colombo last Thursday. Two motorcycle-borne armed men blocked his vehicle and fired at him.

The incident occurred two days after a group of people torched the office of a private TV network near Colombo.

Some sections of the media pointed fingers at the establishment over the killing with private Island newspaper saying in a commentary that "the manner in which the killing was carried out seems to point directly at the government".

Media watchdog Reporters Without Borders alleged that the Mahinda Rajapaksa government was directly to blame for the death of the editor as they had 'incited hatred against him'.

"I feel very sorry about the assassination of Lasantha Wickramatunga. It is very sad for his family, his close friends and associates but it is also a massive blow to democracy and freedom in this country," Kumaratunga said.

"Large number of journalists have been killed or physically attacked...Sirisa MTV channel was burnt just two days before Lasantha Wickramatunga was killed," she said.

"Other journalists have been so threatened that they are beginning to leave the country," Kumaratunga said.

"And I call upon the government of my party, led by my party to please do what is your duty, your responsibility to protect every citizen in this country. Hiding behind all kinds of silly comic allegations that some international conspiracy is responsible for this is no good," the former Sri Lankan President said.

President Rajapaksa has already ordered an investigation into the matter.

"This heinous crime points to the grave dangers faced by the democratic social order of our country, and the existence of forces that will go to the furthest extremes in using terror and criminality to damage our social fabric and bring disrepute to the country," Rajapaksa said.

"It is significant that such an attack was carried out at a time when the country is gaining repeated victories over the forces of terrorism, in our efforts to establish freedom and democracy throughout the country," the President had said in his condolence statement.