MEXICO CITY (Reuters) - Gunmen stormed a hotel in Mexico's central San Luis Potosi state on Tuesday and kidnapped some 20 foreigners believed to be mostly from Haiti and Venezuela, the state's attorney general's office said.

       The gunmen ransacked the building and took off with the logbook of guests, making it hard to identify who was kidnapped at the Sol y Luna hotel in Matehuala, about 195 kilometers (121 miles) north of the city of San Luis Potosi, the regional capital.

       "We are trying to find their identities," Arturo Garza Herrera, the attorney general of the state, said in a statement.

       The authorities have launched an investigation and are trying to rescue the guests, Garza added.

       The statement did not clarify if the kidnapped Haitians and Venezuelans were migrants heading to the United States.

       Many migrants face extreme dangers on their route to the United States, with kidnappings, extortion, rape and even murders reported. Some migrants are also conscripted to work for drug cartels fighting over drug trafficking routes.

       In June, a human rights group reported that some 3,300 migrants stranded in Mexico since January due to a U.S. border policy have been kidnapped, raped, trafficked or assaulted.

       (Reporting by Noe Torres; Writing by Drazen Jorgic; Editing by Dan Grebler)