US support is seen as crucial for Nato membership

He told the leaders of the three countries that their membership would help rejuvenate the two blocs.

Nato and the EU are seen as stabilising factors in the region, especially after the devastating wars of the 1990s.

Mr Cheney is on the final leg of a European tour that also took him to Lithuania and Kazakhstan.

In a speech in Vilnius, he accused Russia of backsliding on democracy.

Praise

Croatia began accession talks with the EU in October and hopes to join by 2009.

Croatia, Macedonia and Albania signed an agreement with the US in May 2003, called the Adriatic Charter, which is designed to facilitate their integration into the Nato alliance.

The US vice-president attended a conference of the Atlantic Charter in the Croatian city of Dubrovnik.

You who aspire to join these organisations help rejuvenate them Dick Cheney US Vice-President

He praised the former Communist countries for their willingness to introduce democratic reforms - as well as for their involvement in US-led military operations in Iraq or Afghanistan.

"You who aspire to join these organisations [Nato and the EU] help rejuvenate them and help us re-dedicate ourselves to the basic and fundamental values of freedom and democracy," Mr Cheney told Ivo Sanader of Croatia, Sali Berisha of Albania and Vlado Buckovski of Macedonia.

"We also believe that it's very important for both Nato and the EU to take in the new members."

Membership of Nato and the EU have been key targets for many Balkan countries.

Such high profile support from the US vice-president is very welcome, especially from governments which have sometimes been criticised domestically for their support of US foreign policy, says the BBC's Nick Hawton in Belgrade.

On the first leg of his trip, Mr Cheney delivered one of the sharpest US rebukes to Russia in years during a speech at an eastern European regional summit in Vilnius, the Lithuanian capital.

He accused Russia of using its vast energy resources to blackmail its neighbours, and said Moscow had a choice to make between pursuing democratic reforms and reversing the gains of the past decade.