A Serbian minister cancelled a visit to his country's former sister state Montenegro on Wednesday in the latest sign of strained relations between the two since they split last year.

Infrastructure Minister Velimir Ilic cancelled his trip to protest Montenegro's refusal to grant entry to a Serbian Orthodox bishop suspected by The Hague of helping ethnic Serb war crime suspects from the Yugoslav wars evade justice.

"If a Serbian bishop cannot enter Montenegro, then a Serbian minister won't either," Beta news agency quoted Ilic as saying from the border with Montenegro after meeting Bishop Filaret.

He said he hoped "the situation with the bishop would not affect the relations and joint projects of the two states". The visit was for talks on a highway linking Belgrade to the Montenegrin port of Bar.

Filaret, a white-bearded 60-year-old known for his Serbian nationalist sympathies, has held a hunger strike on Montenegro's border since Aug. 28.

Montenegro, keen to get The Hague war crimes tribunal's support for its progress towards European Union membership, turned Filaret away several times this summer when he was trying to visit parts of his diocese that are on Montenegrin soil.

Montenegrin Transport Minister Andrija Lompar said his government had information that the Serbs had planned to cancel Ilic's visit all along, calling the move a "political trick".

"So far we haven't got an official or unofficial explanation from Serbia on why their delegation did not arrive," he said.

Relations between Montenegro and Serbia have worsened since the coastal republic voted to leave its 90-year union with its larger sister state in May 2006 against Belgrade's wishes.

The political unease also has a religious side.

Montenegro's predominantly Orthodox population mostly follows the Serbian Orthodox Church, but since the split, that dominance has been challenged by the Montenegrin Orthodox Church, which is not recognised by other Orthodox communities.