The UN refugee agency (UNHCR) has accused Turkish police of causing the deaths of four men by forcing them into a river on the Turkey-Iraq border, BBC reported.
The strong current swept the men away, the UNHCR said, quoting witnesses.
The incident happened on Wednesday at an unpatrolled stretch of the border near the Habur crossing point, in Sirnak province, the UNHCR said.
At least one of the four was an Iranian. They were among 18 Iranians and Syrians refused entry into Iraq.
There has been no comment from the Turkish authorities.
The UNHCR says that in all, the Turkish authorities took 60 people to the Habur crossing for deportation to Iraq, but the Iraqis refused entry to the 18 non-Iraqis in the group.
The UNHCR says it is "seeking clarification from the government of Turkey on the circumstances surrounding the forced expulsion of the refugees and the tragic loss of life".