ANKARA, August 11 (RIA Novosti) - Turkey plans to buy eight missile defense systems abroad to protect itself against possible missile attacks, an undersecretary for the Defense Ministry said on Monday.

Murat Bayar said two missile shields are to be deployed in and around Ankara and Istanbul by 2010, and that Turkey is currently negotiating a deal with four countries: Russia, the United States, China and Israel.

Experts say the most effective systems for Turkey would be the Russian-made S-300/400 or the U.S. Patriot missile defense systems. The United States deployed Patriots in Turkey during the war in the Persian Gulf and the U.S.-led invasion of Iraq.

Bayar said four systems would be bought initially and deployed to protect the Turkish capital.

"Systems that will be bought later will be deployed in other areas, depending on the threats encountered by the country," he said.

The cost of the Turkish air defense system has been put at $1 billion.