Turkish Foreign Minister Ahmet Davutoglu said on Tuesday that NATO member Ankara would formally ask the alliance for Patriot missiles to protect its border with conflict-wracked Syria.

"(Patriots) are a precautionary measure, for defence in particular," Davutoglu told reporters before he left Ankara for Gaza. "We will submit the formal request as soon as possible."

Davutoglu's comments came a day after NATO chief Anders Fogh Rasmussen said the alliance had received no formal request from Turkey for the surface-to-air missiles, but that it would consider the matter with "urgency" if a request was made.

Davutoglu did not elaborate on the details of the Patriot deployment but said Ankara was "in the last phase of talks" before the request went through.

Turkey's border villages have been hit by artillery fire from Syria as forces loyal to Damascus battle rebels seeking to oust President Bashar al-Assad's regime.

"It is the very mission of NATO to supply the security of its members, when one of them is threatened by this level of border violations and faced with even further risks, like ballistic missiles," Davutoglu said.

Ankara has been strengthening its defences along the border with anti-aircraft batteries and tanks since June 22, when one of its F4 fighter jets was downed by Syria along with two pilots for a brief violation of Syrian airspace.

Turkey's ties with its former ally Syria hit a new low on October 3 when Syrian shells fired across the border killed five Turkish civilians, three of them children.

The Turkish military has since been firing mortars into Syria to reciprocate every Syrian shell falling on its territory.

Ankara has already asked NATO to take measures to protect its border and contain the Syrian conflict, which has killed some 37,000 people in 20 months and sent more than 120,000 refugees into Turkey.

But its pleas to set up a safe haven inside Syria for people fleeing the conflict fell on deaf ears at a UN Security Council meeting in August. Turkish media have speculated the Patriot system could be used to create a de facto safe zone in northern Syria without backup from ground troops.

Rasmussen said however there was currently no question of imposing a no-fly zone with the back-up of the Patriot missiles, which are capable of intercepting both aircraft and missiles.

Germany and The Netherlands are the two main European nations that possess Patriots, medium-range ground-to-air missiles made by US group Raytheon. NATO deployed the missiles in Turkey during the 1991 Gulf war and in 2003 during the Iraqi conflict.

The Patriots will play a vital role for Turkey, which seeks to beef up its air defence systems, according to officials in Ankara.