Three wolves which were thought to have settled in the Netherlands have disappeared without trace and are feared dead.

Animal protection organisation Zoogdierenvereniging said it is possible the animals could have drowned, or hit by a car, although that would have been reported to the police.

‘But it may have been hunters and we cannot ignore the possibility. Farmers do not like the wolves because they are afraid they will attack their sheep,’ spokesman Glenn Lelieveld told Trouw.

Earlier the Flemish forestry commission announced a pregnant female wolf which had crossed into Belgium from the Netherlands, had probably fallen victim to hunters. There was no sign of her young and her body has not been found.

The three missing wolves were all from German packs. In March one of the wolves, a female named Janka, attacked sheep in Drenthe, while one male was spotted in Overijssel and Drenthe. Another male was filmed crossing the A28 near Putten on the Veluwe. Of the three wolves, only the female was fitted with a GPS device.

Lelieveld said the preventive measures which are in place in Gelderland, such as subsidies for farmers to install electric fences, are the way forward. ‘If you see a wolf don’t put it on social media but tell us. Otherwise people might come and disturb the wolves or harm them,’ he told the paper.

Since 2015 some 16 wolves have been spotted in the Netherlands, the Zoogdierenvereniging said. Four were killed in traffic, two crossed the border to Belgium, three settled in the Veluwe area, including two who have since had five cubs, and four went back to Germany.

Wolves have protected status in the Netherlands but despite measures to compensate farmers for the loss of animals, their return remains controversial.