The family of slain former premier Rafik Hariri (search) called Thursday for an internationally led investigation into his assassination as pressure mounted to catch his killers, setting the scene for a standoff with the Syrian-backed Lebanese government.

Lebanon's government opposes a foreign-led investigation into Monday's blast that killed Hariri and 16 others. It has, however, requested foreign investigators, including Swiss forensic and explosives experts, assist the inquiry. Many Lebanese, including Hariri's supporters, accuse Syria and the Lebanese government of orchestrating the attack and fear a domestic probe will lead nowhere.

Both governments have denied any involvement.

"We call upon the international community to promptly take control of this issue and form an international investigation commission, since the assassination of Rafik Hariri is a terrorist act targeting Lebanon's stability and national unity," said a statement released by Hariri's family.

"We will not spare any effort or means to find the perpetrators of this crime no matter what their affiliation is," the statement said.

Many Lebanese are seething over the death of Hariri, whom they credit with rebuilding their country following the devastating 1975-90 civil war, and more than 200,000 mourners attended his funeral Wednesday. Government officials did not attend, at the insistence of Hariri's family.

Hariri resigned as prime minister last year amid opposition to a Syrian-backed constitutional amendment that extended the presidency of his rival, Damascus ally Emile Lahoud (search).

Lebanese Interior Minister Suleiman Franjieh, who paid a condolence call to Hariri's home Thursday, afterward renewed his government's opposition to calls for an international investigation.

"We have said that we can seek help from international experts. But we cannot abandon our role and bring in (foreign) states to investigate," he said.

Hariri, a charismatic man whose wealth and prominence gave him some degree of independence from Syria's political influence in Lebanon, led his country for 10 of 14 years following the war and was expected to stand in parliamentary elections scheduled for April and May. He had not ruled out another run for the prime ministership.

The intense international pressure to find his killers has increased anxieties in Lebanon and its neighboring powerbroker, Syria, which has announced it is seeking stronger cooperation with Iran. Washington's ire has been directed at both — Iran for its nuclear ambitions and Syria for its alleged ties to terrorism — and talk of an alliance to confront possible threats stirred considerable concern.

Word of the alliance came as Washington recalled its ambassador to Syria. France also backs renewed U.S. calls for Syria to withdraw its 15,000 troops from Lebanon, where they have been based since the early stages of the civil war. Syrian Foreign Minister Farouk al-Sharaa said earlier this month that Syria has 15,000-16,000 troops in Lebanon.

Paris, Washington and the United Nations Security Council have demanded the Lebanese government urgently investigate the killing and bring the culprits to justice.

The U.S. representative at the funeral, Assistant Secretary of State William Burns, demanded a thorough murder investigation.

"I don't know who is responsible for this horrible act of terrorism. What I know is that those who are responsible need to be brought to justice quickly," Burns said.

Lebanese investigators continued searching for clues at the seafront bomb scene marked by huge crater, blackened hulks of burned out cars and onlookers standing behind police and yellow tape. Investigators, however, have been tightlipped about evidence surfacing.

"I cannot predict when we will get the results, but I can say one thing — every day reveals something new," Franjieh told reporters at Hariri's palace after offering condolences.

Franjieh's own father, Christian militia leader Tony Franjieh (search), was killed in 1978 by Christian rivals who were never brought to justice.

Lebanon has a history of not tracking down those responsible for political assassinations, including the 1989 assassins of Grand Mufti Hassan Khaled and President-elect Rene Mouawad, who died in separate car bombings, and the 2002 killers of Christian warlord Elie Hobeika.

Franjieh said authorities are investigating the videotape broadcast Monday by Al-Jazeera TV that showed a purported Palestinian extremist from an unknown militant group claiming responsibility for assassinating Hariri. That claim had, however, appeared to lack credibility.

"We have something in our hands: the tape and a specific group that was operating. We are investigating this and we will see where this will lead us to. We cannot predict," said Franjieh, who had previously suggested a suicide bomber backed by "international parties" may have carried out the attack.

After the tape's initial airing, Lebanese security forces raided the west Beirut home of Palestinian Ahmed Abu Adas, who they said was the man in the video, but had apparently fled earlier in the day. They confiscated computers, tapes and documents. The man's whereabouts are unknown.

Some have suggested the killing was carried out by rogue Syrian intelligence operatives or even factions among Lebanon's myriad religious groups.