Exceptional security measures are being planned by Italy for a NATO-Russia summit scheduled for Tuesday just outside Rome. Italian authorities are taking nothing for granted as they prepare for a landmark signing ceremony. A security force more than 15,000 strong will patrol the area around the air base hosting the summit. Twenty heads of state and government are to take part in the one-day meeting Tuesday, including U.S. President Bush and his Russian counterpart, Vladimir Putin.

NATO and Russia will sign a cooperation agreement at the summit, aimed at giving Moscow a greater role in the military alliance. The accord has been hailed as marking the end of the Cold War.

The signing ceremony will be held at an air base at Pratica di Mare, about 15 kilometers south of the Italian capital.

Major precautions are being taken to ensure security, including a naval exclusion zone around the base for the day of the summit. NATO's AWACS surveillance planes and Italian coastguard vessels will be on patrol. An anti-missile system will also be deployed.

Security will be extremely tight at Rome's main passenger airport, Leonardo da Vinci. The Italian authorities are taking no chances, and special measures have been adopted to prevent any possible suicide missions like the September 11 terrorist attacks in the United States.

Italian officials said air marshals will be aboard civilian planes flying in and out of the airport Tuesday. In addition, a decision is pending on whether to completely close the airport to all traffic during the summit.

Rome's second airport, Ciampino, will be closed to commercial flights and its use reserved exclusively for VIPs.