MEXICO CITY (Reuters) - Mexico’s government said on Thursday that it would look into a report that Cuban migrants had been kidnapped by an organized crime group just south of the U.S. border, adding to existing probes into disappearances of migrants in the area.

Four Cubans trying to enter the United States from the border city of Reynosa in Tamaulipas state last weekend were abducted by a group that is now demanding ransom, Mexican newspaper El Universal reported on Thursday, citing interviews with family members of the migrants.

The state government told Reuters no complaints had been filed related to the alleged kidnapping.

Mexico’s Security Minister Alfonso Durazo said at the president’s regular news conference that the report would be taken into account as other investigations proceed.

Officials are also examining the disappearance of 22 passengers, thought to be migrants, who were kidnapped by armed men from a bus in Tamaulipas last week. Durazo said officials are working with other countries to review the bus passenger list and check for reports of missing people.

For years, Tamaulipas has suffered high levels of murders and disappearances amid clashes between violent criminal gangs.

In August 2010, 72 undocumented migrants from Central and South America were murdered by the Zetas gang at a ranch in Tamaulipas. A year later, nearly 200 corpses, many of them Mexicans, were found in mass graves in the area.

Mexico is also grappling with corruption within its migration authorities and is investigating reports that border agents extorted migrants, Interior Minister Olga Sanchez Cordero said.

“Without a doubt, the National Migration Institute was one of the institutions most permeated by corruption,” she said. “We’re replacing practically the entire staff.”