Ankara, Jul 12 (IANS): The first shipment of Russian S-400 missile defence system hardware to Turkey started on Friday, the country's Defence Ministry has announced.

"First batch of equipment of S-400 missile defence system, which is procured to meet Turkey's air and missile defence need, has started to arrive at Murted Air Base in Ankara," the state-run Anadolu News agency quoted the Ministry as saying on Twitter.

In December 2017, Ankara and Moscow signed a $2.5 billion agreement for two batteries of the S-400 system, Russia's most advanced long-range anti-aircraft missile system.

Turkey is the first NATO member country to acquire the system, Xinhua news agency reported.

Ankara's cooperation with Russia on this missile system has been strongly criticized by Turkey's NATO ally, the US.

In April, the Pentagon claimed that Turkey's adoption of Russian missile could cause security risk on F-35 jets and NATO defence systeml.

US President Donald Trump's administration has also threatened to impose severe sanctions on Turkey if the S-400 missiles deal with Moscow was followed through.

However, Turkey has refused to bow to US pressure, insisting that choosing which equipment to purchase is a matter of national sovereignty and does not target any third country.

Earlier this month, Turkish President Recep Tayyip Erdogan said that the dispute between Ankara and Washington on the S-400 issue would be resolved "without any problem".

Erdogan recalled that Ankara wanted to buy US Patriot systems during the term of former US President Barack Obama but Washington declined Ankara's demand at the time.