Mr Dole applied for a visa more than a week ago, but it had not been granted by the time he departed for the region.

"We certainly hope that [Yugoslav President Slobodan] Milosevic and the Serbs don't try to use this visa issue as an excuse to derail a mission of peace," spokesman Doug MacKinnon said.

Jackie Rowland reports on the state of the peace agreement

US officials have said that if Mr Dole fails to reach Kosovo's capital Pristina by road, he will try to arrange meetings in neighbouring Macedonia, which is his initial destination.

Mr Dole is reportedly optimistic that he will be able to persuade the ethnic Albanians to endorse the autonomy deal negotiated at last month's Paris peace conference.

Bob Dole could be forced to hold negotiations in Macedonia

A key negotiator for the ethnic Albanian Kosovo Liberation Army has told the BBC that the rebels are ready to approve a peace deal.

KLA commander Rame Buja said that 90% of his men supported the deal hammered out in France, even though it fell far short of full independence for Kosovo.

However, the Clinton administration is more pessimistic about the possibility of reaching an agreement with the Serbs, who object to proposals for Nato troops to enforce the agreement.

With just 10 days to go before the two sides are due to meet for a new round of peace talks, more fighting has been reported between Serbian troops and the KLA.

Border guards on either side of the province's border with Albania are reported to have exchanged fire for the first time since the conflict started.

Albright flies to London

Serb security forces have been involved in border clashed with the KLA

In further diplomatic moves, UK Foreign Secretary Robin Cook is due to meet the Russian Prime Minister, Yevgeni Primakov, in Sochi on the Black Sea on Friday.

He is expected to go on to Moscow for talks with his Russian counterpart, Igor Ivanov. Both meetings are likely to look at the issue of peace in the Balkans.

The US Secretary of State, Madeleine Albright, is reported to have arranged an unexpected detour to London to set up meetings on Kosovo with British officials.