NEW YORK - Just a week before the second anniversary of the incendiary murder of a one-time Lebanese prime minister, the Lebanese government and the United Nations on Tuesday signed an agreement to establish a special tribunal to try those responsible for murdering Rafik Hariri.

The controversial plans for the tribunal have fuelled street protests and killings in Lebanon over the past two months and raised the tension levels between the western-backed government of Prime Minister Fouad Seniora and the opposition Muslim militant supporters of Hezbollah.

The signing for the tribunal took place in Beirut and was announced at UN headquarters by the director general of the Lebanese Justice Ministry and Nicholas Michel, the UN legal counsel.

'It is up to the competent Lebanese authorities to take the steps necessary under the Lebanese constitution for the approval and ratification of the agreement, to allow it to enter into force,' the UN said in a statement.

'The tribunal could then be made operational with the full support of the UN,' the statement said.

Hariri and 22 other people nearby were killed on February 14, 2005, by a massive bomb explosion on a Beirut street.

The UN has been investigating the murder at the request of the Lebanese government. An independent investigator has suspected Lebanese and Syrian security forces' involvement in the act because Hariri was well known for his opposition to Syrian military occupation of Lebanon.

Shaken by accusations that it took part in the murder and pushed by international pressure, Syria pulled its military and intelligence forces out of Lebanon in May, 2005, after more than two decades of occupation of part of its neighbour.

Over the past year, anti-government groups ave been demanding that Seniora's Western-backed government give way to a national unity government.

The government`s refusal to resign and last year's tentative decision to approve the UN tribunal provoked six pro-Syrian ministers to quit in November and successive street protests aimed at toppling the government.

On November 21, while the opposition was preparing to take to the streets, anti-Syrian Industry Minister Pierre Gemayel was gunned down in broad daylight in a Christian neighbourhood.

Street battles have killed several people and wounded hundreds since then, leading to fears of a resurgence of the sectarian strife that tore the country apart during the 1975-1990 civil war. (DPA)