Sixty trucks and four fuel tankers crossed early on Tuesday morning at the Roeszke border terminal.

But four fuel tankers and five armoured vehicles were not allowed passage because the Hungarian authorities feared they could be used for military purposes in violation of a 1998 UN Security Council arms embargo.

Clearance for the remainder of the convoy was only achieved after Russia sent Emergencies Minister Sergei Shoygu to negotiate, while warning the Hungarian action could threaten future relations between the two countries.

Mr Shoygu said the convoy was carrying food, medicine and tents, which was intended for " everybody in Yugoslavia, independent of the situation, who fell victim to the conflict there."

It was organised by the Russian Ministry for Emergency Relief, and had been due to arrive in Belgrade on Sunday morning as a goodwill gesture from fellow orthodox Christians in time for the Christian Orthodox Easter.

Russian officials accused Hungary of deliberately obstructing the convoy out of loyalty to Nato, which it recently joined.