The UN Security Council has agreed to a request from
The council's current president said the decision was taken quickly and needed no discussion.
The UN commission already looking into the murder of ex-Lebanese PM Rafik Hariri in 2005 will take on the probe.
Many in
Mr Gemayel,
Crowds have gathered in Mr Gemayel's village for his funeral on Thursday.
Earlier on Wednesday US President George W Bush called Lebanese Prime Minister Fouad Siniora to pledge support for
Tribunal
The Security Council's announcement came shortly after UN Secretary-General Kofi Annan expressed his concern over events in
The BBC's UN correspondent in
She says the tribunal could also eventually try Mr Gemayel's killers but such a tribunal is highly controversial in
Pro-Syrian politicians are against it, she says, and it cannot begin to be set up until the Lebanese parliament votes for it.
Mr Gemayel's killing has created a political crisis in
The Security Council's quick decision followed calls from US Ambassador John Bolton for rapid action "while the crime scene evidence is still fresh".
The UN inquiry already in place, led by Belgian prosecutor Serge Brammertz, is also looking into another 15 apparently politically motivated attacks, including Mr Hariri's death.
In his telephone call to Mr Siniora, Mr Bush reiterated the "unwavering commitment of the
Mr Bush has not specifically blamed
A huge crowd of mourners accompanied Mr Gemayel's coffin as it arrived in his home
Mr Gemayel's supporters have called for a mass turnout at his funeral, and there is a large military presence both in the village and in
Photo Caption
Pierre Gemayel