ATHENS (Reuters) - Cyprus said on Wednesday it would protest to the United Nations over Turkish Cypriot restrictions imposed on humanitarian aid to Greek Cypriots living in the north of the partitioned island, in a sign of deteriorating relations between the two sides.

A U.N. peacekeeping force has been transporting a range of household supplies to a small and dwindling community of Greek Cypriots and Maronite Christians based in the Turkish Cypriot-controlled north of the island for decades.

Turkish Cypriot officials last month announced they would start charging customs duties on goods, with the exception of medical aid, effective from Oct. 1. An aid convoy sent via the United Nations on Wednesday contained only medicine.

Only Turkey recognizes the breakaway Turkish Cypriot state, and Cyprus’s internationally recognized government views any customs payments out of the question.

“These measures... which are totally illegal and contrary to all agreements, are polluting the good climate we want to maintain every way possible,” said Greek Cypriot President Nicos Anastasiades.

“This will be reported, with steps and measures if necessary,” he said, without elaborating.

Wednesday’s incident underscored a deterioration in relations between the two sides since the collapse of revived peace negotiations in Switzerland in July.

In a statement, the U.N. peacekeeping force expressed “regret” at the decision taken by the Turkish Cypriot administration.

A weekly convoy on Wednesday carried only medical supplies to the 264 elderly Greek Cypriot recipients of aid, the United Nations said. Another convoy takes aid to Maronite recipients every other week. The Maronites are descendants of Arabs who moved to Cyprus many centuries ago from what is now Lebanon.

Turkish Cypriot officials were last month quoted in Cypriot media as saying aid, which ranged from gas cylinders to food, was being sold on to others, and that it was not required.

Cyprus was split in a Turkish invasion in 1974 triggered by a brief Greek inspired coup, resulting in tens of thousands of internally displaced people.

Crossing points opened in 2003 and today there is a regular stream of traffic from one side of the island to the other.

Greek Cypriots regularly visit the north for cheaper tobacco products and medicine - even though that is formally banned - and Turkish Cypriots go to the south for grocery shopping.