Polish divers have found the body of a Syrian man, 19, in a river on the Belarusian border as pressure on the frontier mounts from increasing numbers of migrants seeking access to Europe.
Poland, Lithuania and Latvia have reported sharp increases in the number migrants from countries such as Afghanistan and Iraq trying to cross their borders from Belarus.
Warsaw and Brussels say the movement from Belarus is designed to put pressure on the EU over sanctions it imposed on Minsk.
Border guards had been looking for the man since Tuesday when they apprehended another Syrian who said he and a compatriot were pushed into the river by Belarusian officers, the state news agency reported.
Divers found the body on Wednesday in the River Bug, which forms part of the border between Poland and Belarus.
"His identity was confirmed by the other young man with whom he tried to illegally cross the Bug a day earlier," Lublin region police spokesman Andrzej Fijolek said.
"We also found documents on the body. So there is no doubt that's the 19-year-old Syrian citizen."
Mr Fijolek said an investigation would be conducted into the death.
Horst Seehofer, Germany's Interior Minister, has said Poland needs additional support to help control the influx. It was in no country's interest to see controls on Poland's border with Germany, he said.
Human rights groups have criticised Poland's nationalist government over its treatment of migrants at the border, accusing it of pushing them away.
Six people have been found dead near the border since the surge of migrants from Belarus began.
Polish authorities said guards at the frontier had this month foiled 6,700 attempts to cross the border illegally, and more than 10,000 since August. Another 1,500 people were detained in Poland and taken to guarded facilities.