BRATISLAVA (Reuters) - Slovak customs officers injured a Syrian woman on Monday when they shot at a car carrying migrants from Hungary into Slovakia, authorities said.

Police in Europe have sometimes used water cannon and tear gas to prevent migrants from crossing borders but this may be the first reported incident inside the continent’s passport-free Schengen zone where migrants have been shot at.

The officers stopped four passenger cars entering Slovakia from Hungary in the early hours of Monday, the Financial Administration that runs the customs service said in a press release.

Three cars complied with an order to stop but the fourth tried to escape and endangered three officers, it said.

“The officers fired warning shots and when the car did not stop they fired at the car, injuring one person,” it said, without further details.

A hospital in Dunajska Streda, southern Slovakia, said the injured person was a Syrian woman aged about 26 and that she was in a stable condition after undergoing surgery to remove a bullet from her back.

The hospital said it had also treated two migrants suffering from dehydration.

The cars and the passengers were handed over to the border police, the Financial Administration said.

Slovakia has so far seen only a trickle of migrants trying to cross its territory to reach Germany, the favoured destination for people fleeing conflicts and poverty in the Middle East and beyond. But the government fears tighter border controls by neighbouring Austria could prompt more migrants to use Slovakia as a stepping stone from Hungary as they head west.