"Hit-to-Kill" Patriot missiles set to be deployed on the Turkish-Syrian border are a sophisticated anti-ballistic defence system developed by arms manufacturer Lockheed Martin for the US Army.

Dubbed by its US manfacturers as "the world's most advanced, capable, and powerful terminal air defense missile," the Patriot Advanced Capability-3 (PAC-3) is said to take out cruise and ballistic missiles as well as aircraft.

But it is designed as a purely defensive system, NATO chief Anders Fogh Rasmussen stressed Tuesday as the North Atlantic alliance approved Turkey's request to station several batteries along its volatile border with Syria.

The system has been adopted by several countries, and United States, Germany and the Netherlands have agreed to contribute to the patriot deployment, NATO said in a statement.

But the number of batteries, as well as their precise location, has yet to be decided and will be determined following the results of a site survey in Turkey and after consultations and decisions by each contributing country.

The missiles were first conceived of in the 1960s at the height of the Cold War between the United States and the Soviet Union but only entered service in the 1980s.

The PAC-3 is the latest generation, with 16 missiles loaded onto a single launcher compared with four of the previous PAC-2 generation.

The Patriot -- 'Phased Array Tracking Radar to Intercept on Target -- came into its own during the 1991 Gulf War when they were deployed in the Gulf to protect allies and US forces from Iraqi Scud missiles -- their boxy launch units became instantly recognisable in TV images of the conflict.

A high-velocity missile, the PAC-3 destroys incoming targets by directly smashing into them, "defeating enemy target by direct body-to-body contact," Lockheed Martin says on its website.

They speed towards an impact point calculated before their launch by a sophisticated radar and tracking system on the ground. But they can be re-directed once launched thanks to an on-board guidance system.

The time from launch to point of impact is usually only between a minute to 90 seconds.

NATO foreign ministers meeting Brussels agreed Tuesday to deploy Patriots along the 800-kilometre (500-mile) border with Syria after a series of strikes by Syrian artillery fire in recent months.

It will still take several weeks for them to be installed but the system is designed so that contributions from various countries are inter-operable.