Tadic was flown in by a NATO-backed peacekeepers to meet with Orthodox monks at the Visoki Decani monastery in the north-west of Kosovo.

"My message today in Decani is a message of peace for Serbs, peace for Albanians, peace for all people living in Kosovo, in our Serbia," Tadic told reporters after lighting a candle in the church.

While Serbian sources said that Tadic had not asked formally for permission to enter, Kosovar sources said that they had granted permission.

According to reports, Kosovar authorities initially refused entry, but changed their mind on Thursday evening after strong diplomatic pressure from the US and European Union.

Kosovo's prime minister, Hashim Thaci, said his government had decided to allow the trip because it "considers this visit as entirely a private and religious one."

Kosovo declared independence from Serbia in February of last year and was recognized by the US and most members of the EU. Serbia bitterly opposed the move and Tadic has repeatedly said that Belgrade would never recognize an independent Kosovo and always consider it Serbian territory.

International court case

The Orthodox Good Friday trip, Tadic's first since last Easter, coincided with a deadline for both Kosovo and Serbia to present their cases to the ICJ arguing for or against Kosovo's declaration of independence.

The 1,000-page Serbian submission "has all necessary elements and legal arguments to prove that the proclamation of Kosovo's independence is not in accordance with international law," the Serbian Foreign Ministry said in a statement, according to the Beta news agency.

Last year the United Nations General Assembly called on the ICJ to adjudicate over the legality of Pristina's independence declaration. The move came after heavy lobbying from Belgrade.

An ideal outcome for Serbia would see the ICJ stop countries from recognizing Kosovo's independence and restart negotiations on its status.

So far, 57 countries have recognized Kosovo's independence, including all but five of the EU's 27 member states. Cyprus, Greece, Romania, Slovakia and Spain have turned their backs on Kosovo's move to become a nation either in solidarity with Belgrade or in fear the move could encourage separatists at home.

Serbia is currently recognized as a candidate country for joining the EU, though any accession would not likely occur before 2012.