TALLINN, July 7 (RIA Novosti) - NATO states will start in the Baltic states on Tuesday a series of air defense exercises involving Czech fighter jets, the Estonian Defense Ministry said.

The two-day drills are focused on improving air interoperability and developing NATO air forces' capabilities in defending the air space over the Baltic states of Estonia, Latvia and Lithuania.

The exercises will involve four Czech JAS-39 Gripen fighter jets, based at the Lithuanian Siauliai Air Base, and a U.S. C-130 Hercules military transport plane.

The exercises are a continuation of NATO's air policing drills, held last October and this April.

NATO's air policing is one of the key aspects of common security and defense for the Alliance. In the case of the three Baltic states, the alliance rotates air policing capabilities.

The Czech Air Force took over Baltic air policing from the Royal Danish Air Force on May 1. At the end of its leg, the Czech Republic will hand over the NATO mission to the German Air Force later this year.

A NATO agreement on airspace security over Lithuania, Latvia and Estonia is set to expire in 2011, and the three countries are currently pushing for the agreement to be extended to 2018.