Serbia's defence ministry said the two jets had touched down at the Batajnica military airport on a "visit that is a part of the process of increasing military cooperation between Serbia and the United States."

The ministry described the visit as a "historic event" as it was the first time that American fighter planes had landed at a Serbian military base.

The visit was agreed after Serbian defence officials met the deputy commander of US forces in Europe, General Charles Wald, during a visit to Belgrade in March, the ministry said.

The two fighter jets were a part of the US Air Force stationed in Europe, the ministry said.

Serbia-US relations have gradually improved following the ouster of Serbian strongman Slobodan Milosevic in 2000.

Milosevic died in his prison cell at the UN war crimes tribunal in March during his trial for his role in a series of wars that had torn the former Yugoslavia apart in 1990s.

In 1999, the NATO alliance launched a bombing campaing on Serbia in a bid to halt a crackdown by Milosevic's regime on independence-seeking ethnic Albanians in the southern Serbian Kosovo province.

In the 78 day air war, Serbian forces downed a US F-16 near the western town Sabac on May 1, 1999.

The engine and tail of the plane, complete with markings, have since been on display at the Nikola Tesla Airport Museum.

After Milosevic's ouster the new authorities in Belgrade have opted to join NATO's Partnership for Peace programme, but this has yet to be realized because of Serbia's failure to arrest indicted war crimes suspects, notably former Bosnian Serb military leader Ratko Mladic.