The Democratic Front for the Liberation of Palestine has claimed responsibility for the attacks on the World Trade Center, according to the BBC and Abu Dhabi television.
However, DFLP sources have denied any involvement.
It is unclear who is responsible for today's apparent terrorist attack on the World Trade Center in New York, but it is unlikely that Palestinian groups are involved, said an expert on international terrorism.
"They have a lot to lose because America would react very harshly against the Palestinians, however it is not impossible that a radical group was involved," said Eli Carmon, of the Herzliya Interdisciplinary Center's counter-terrorism department.
Carmon noted that the World Trade Center has been targeted once before in
1993, when a bombing killed six people and injured more than 1,000.
Carmon said that there have been threats by unidentified Islamic groups to target
the World Trade Center again if Sheikh Omar Abdul Rahman, the militant
Egyptian cleric, who is serving a life sentence in the US after his conviction in a plot to bomb the United Nations and New York landmarks, was not released.
He added that it is possible that terrorist mastermind Osama Bin-Laden is
Carmon said that the alleged terrorist attack amounts to a "declaration of
war" on the US, and that the US will have to "react in an extremely harsh