Egypt is investigating reports that people traffickers are holding up to 300 Eritreans hostage in the Sinai Peninsula, a senior security official told AFP on Wednesday.
"So far we have not confirmed these reports given by local media" that about 300 migrants were being held hostage by traffickers in a mountainous region near the border with Israel, the official said.
Police were quizzing individuals allegedly close to known traffickers, he said.
On Tuesday, the United Nations High Commissioner for Refugees said it was concerned about 250 Eritrean migrants believed to be held hostage in the Sinai desert.
"We have noted media reports that the traffickers are demanding payments of 8,000 dollars per person for their release, that people are being held in containers and are subject to abuses," a statement in Geneva said.
The Sinai desert border has become a major trafficking route for African migrants seeking jobs. Thousands of Eritreans each year flee the country, with many heading for Israel.
In August, seven people were killed in clashes with smugglers and police near the border with Israel after African migrants being held by traffickers seized the weapons of their captors in a bid to escape.
Israel began work in November on a 250-kilometre (155-mile) fence along the Egyptian border aimed at stopping the influx of migrants.
In October, the New York-based Human Rights Watch urged Egypt to stop shooting migrants, saying its security forces had killed at least 85 migrants trying to enter Israel since 2007.