US-made Patriot missiles will not be deployed right at Turkey's volatile border with Syria but rather a short distance away, a move to reassure Russia that they are only for defence purposes, a diplomatic source said on Monday.

"We want to keep the missiles away from the border in order not to cause any misunderstanding with Russia and to make it clear that their deployment is purely to defend Turkish territory," he said.

NATO last week approved Turkey's request for Patriot missiles to defend its border against Syria following a series of blunt warnings to Damascus not to use chemical weapons.

Russia, a key ally of the Syrian regime, is opposed to the move fearing that such a deployment could spark broader conflict in the region and also draw in NATO.

In Istanbul last Monday Russian President Vladimir Putin warned that any deployment of Patriot missiles near the volatile border would exacerbate tensions.

"You know, as they say, if a gun is hung on the wall at the start of a play then at the end of the play it will definitely fire," Putin told reporters after meeting with Turkish Prime Minister Recep Tayyip Erdogan.

"Why should we need extra shooting at the border? We are urging restraint."

The diplomatic source in Ankara said the location for the deployment of Patriot missiles was very important.

"The Patriots will be deployed more than 10 kilometres (six miles) away from the border but this will not compromise on the effectiveness of the system," according to the source.

NATO said that Germany along with the Netherlands and the United States has agreed to provide the Patriot missile batteries, which would come under the command of the alliance.

The German government said last week it had approved deploying Patriot missiles to help NATO member state Turkey defend its border against Syria and will send up to 400 troops.

But the move still needs to be approved by the German parliament, which will discuss the deployment on Wednesday.

Although sending troops abroad remains a controversial issue for Germany, it is likely to be approved, said the source, noting that the deployment of Patriots would cost 25 million euros for Germany alone.

"The Patriots will be deployed in the beginning of next year at the earliest," he said.

Although the mandate runs until the end of January 2014, it might be extended depending on the situation on the ground.

The Patriot deployment can also order the use of Airborne Warning and Control Systems (AWACS), he said.

"It makes sense to put Patriots together with AWACS. Germany can provide the use of the AWACS system in short notice."

It is not yet clear how many Patriot batteries Germany would provide but the Netherlands is due to send two Patriot batteries, along with a maximum of 360 soldiers.

The deployment of Patriots was also a logistical issue "because the systems are heavy," the source noted.

He added: "An airplane might be quicker but they might also be sent by ship."

Turkey is a vocal opponent of President Bashar al-Assad's regime in Syria, where monitoring groups say more than 41,000 people have been killed in almost 21 months of conflict.