Photo: Perry Aston / U.S. Air Force

Ukraine cannot use the F-16 fighter jets Denmark will provide outside its territory, Danish defence minister Jakob Ellemann-Jensen told Ritzau news agency.

"We donate weapons under the condition that they are used to drive the enemy out of the territory of Ukraine. And no further than that", Mr Ellemann-Jensen said.

"Those are the conditions, whether it's tanks, fighter planes or something else," he said.

On Sunday, Denmark announced that it would donate 19 F-16 aircraft to Ukraine, while the Netherlands would transfer some of the 42 fighter jets it is currently replacing with more modern F-35s.

In May, US president Joe Biden officially confirmed that the US military would start training Ukrainian pilots for the F-16, which already started last week.

Ukraine, which has long been pushing for modern fighter jets, has indicated it needs four squadrons, that is 48 F-16s, to effectively deter Russian aggression.