At least 17 people died in flash floods in the Macedonian capital Skopje during a storm on Saturday evening, Deputy Prime Minister Nikola Todorov said on Sunday, warning that the death toll could rise further.

Torrential rains had swept away a section of the ring road around Skopje and some cars had been carried hundreds of metres into nearby fields, a Reuters reporter said.

"This is a catastrophe of unprecedented proportion," Todorov said. He said he had received unconfirmed reports of three further deaths.

Northern suburbs of Skopje were particularly hard hit, with many homes flooded. There were also flash floods in the city centre, according to the reporter.

Police had said earlier that 22 people had been hurt during the storm.

Special police forces and trucks loaded with drinking water were heading for the most affected areas, and there some electricity outages, the Reuters reporter said.

The rain had stopped on Sunday morning and water levels were receding, but more rain was forecast for the evening in the capital of the small Balkan nation of 2 million inhabitants.

European Union Enlargement Commissioner Johannes Hahn said on Twitter that the EU stood ready to help Macedonia, which is a candidate to join the bloc.

Further north in the Balkans, in Croatia, heavy winds caused disruptions on some roads, including the closure of the highway linking the capital Zagreb to southern coast for lorries and buses, local media said.  - Reuters