MOSCOW, Sept. 15 (Xinhua) -- The Russian Defense Ministry said the second phase of delivery of S-400 air defense system components to Turkey was completed on Sunday.

The supply was made in accordance with the agreements reached between Russian President Vladimir Putin and his Turkish counterpart Recep Tayyip Erdogan on improving the air defense capability of Turkey, the ministry said.

The first stage of such delivery took place in July despite strong U.S. opposition and the deployment of the S-400 missiles is likely to begin in October, according to the Turkish Defense Ministry.

In 2017, Russia and Turkey finalized a deal to supply Ankara with two batches of S-400 surface-to-air missile batteries. In April 2018, both parties agreed on early delivery of the weapon.

The S-400 air defense missile system is considered the most advanced of its kind in Russia, capable of destroying targets at a distance of up to 400 km and a height of up to 30 km.