May 13, 2007 10:03 PM

BELGRADE, May 14-(Kyodo), Tomislav Nikolic, acting president of the rightist Serbian Radical Party, who was elected speaker of the Serbian parliament only last week, stepped down Sunday to avoid being ousted by the newly formed government majority of pro-democratic and pro-European parties.

Nikolic, 55, assumed Serbia's third most important position on Tuesday with the support of deputies from caretaker Prime Minister Vojislav Kostunica's Democratic Party of Serbia.

But his election shocked other European countries which felt it signaled Belgrade's turn toward extreme nationalism at a time when the final resolution of the complex Kosovo issue is expected.

Nikolic, a law school dropout, founded the Serbian Radical Party in 1990 but later handed over the leadership to Vojislav Seselj, who is currently being tried for war crimes by the U.N. War Crimes Tribunal in The Hague.

The Serbian Radical Party is demanding that Kosovo, still formally a Serbian province with an Albanian majority population, should remain within Serbia at any cost.

Nikolic's resignation came after Kostunica decided to withdraw his support for the Radicals after making a last minute deal with President Boris Tadic's Democratic Party and the G-17 Plus party of former Finance Minister Mladjan Dinkic.

The Serbian Radical Party advocates the idea of a Great Serbia -- merging parts of Croatia and Bosnia with Serbia, keeping Kosovo at all costs and taking back Montenegro which seceded last year.