MOSCOW, October 20 (RIA Novosti) - Russian President Dmitry Medvedev will focus on the implementation of joint Russian-Serbian energy projects during his official visit to Belgrade on Tuesday.

Medvedev's trip to Serbia, during which he will attend celebrations marking the 65th anniversary of the liberation of Belgrade from Nazi forces, is the first visit to the country by a Russian head of state since Vladimir Putin visited in 2001.

A source in the Kremlin said that "the emphasis [of the visit] will be laid on the implementation of major projects in the sphere of trade and economic cooperation," particularly in the sphere of oil and gas cooperation.

Last week, Russian energy giant Gazprom and Serbia's state gas company initialed an agreement to set up a joint venture to develop a Serbian underground gas depot. The agreement was part of a bilateral governmental deal on cooperation in the oil and gas sector sealed between the two countries in 2008.

Construction of the underground gas depot at Banatski Dvor started in 2005. The gas storage facility will have a capacity of 0.8-1 billion cubic meters. It will be connected to the proposed 25 billion-euro ($36.5 billion) South Stream gas pipeline, intended to annually pump 31 billion cubic meters of Central Asian and Russian gas to the Balkans and on to other European countries, bypassing Ukraine.

The construction of the Banatski Dvor depot is a stage of gas production at a worn-out field which used to have reserves of 3.3bcm.

Moscow also supports Belgrade's view that Kosovo, which unilaterally declared its independence in February 2008, is an indivisible part of Serbia.