The Port Authority of New York and New Jersey said in a statement on Friday it was joining a $7 billion lawsuit filed last week against the Saudi government by an investment firm.

The suit filed in US District Court in Manhattan by Cantor Fitzgerald investment firm accuses the Saudi Arabia Government of providing "funding and material support and substantial assistance" to al-Qaida and Usama bin Ladin.

Cantor lost more than 650 of its employees in the attacks.

The Port Authority's move has been interpreted as an attempt to keep its legal options open before a third anniversary deadline for lawsuits related to September 11.

Seeking damages

"We have a responsibility to the millions of people who live and work in the region as well as to our bondholders to pursue every legal avenue to recover the losses we sustained on September 11," the Port Authority statement said.

"Our proposed action is in line with similar suits filed by other injured parties."

The Cantor suit specifically names four Saudi officials, saying they organised and controlled a network of financial institutions and charities that aided al-Qaida for at least seven years before September 11.

The four are the Saudi Interior Minister Nayif bin Abd al-Aziz Al-Saud, Defence Minister Sultan bin Abd al-Aziz Al-Saud, the governor of Riyadh Salman bin Abd al-Aziz and the former intelligence chief Turki al-Faisal.

Al-Qaida has also been named as a defendant, along with a number of Saudi corporate entities and charities.