TEHRAN -- The U.S. Congress on Tuesday ratified the sale of four AWACS to Turkey, the Turkish daily ***Zaman*** reported on Wednesday.

According to an agreement signed between Ankara and Washington in April, Turkey will buy four AWACS worth around 1.1 billion dollars from Boeing Co.

Turkey could raise its demand from four to six spy planes.

It has been said that money for the purchase of the planes will come from the Support Fund for Turkish Defense Industry.

The Support Fund for the Turkish Defense Industry is an official foundation which provides fund for some Turkish defense expenditures through imposition of tariffs and special taxes from some goods and services.

This is the biggest arms purchase by Turkey in the past ten years.

By purchase of these spy planes Turkey would be able to monitor not only airspace and the Aegean Sea it would find access to military movements in the Middle East, Balkans and the Caucasus.