An Italian government official says four smugglers brandishing Kalashnikovs threatened a Coast Guard motorboat involved in one of several operations that rescued more than 2,000 migrants leaving Libyan shores in one day.

Transport Minister Maurizio Lupi said the gunmen used a small boat Sunday to speed to the scene some 50 miles (80 kilometers) off the coast of Libya, where security is rapidly deteriorating.

After threatening the rescuers who had taken aboard the migrants, three of the smugglers jumped onto the then-empty migrants' boat and took off with it.

Nearly 2,200 migrants were rescued in several operations Sunday, the Coast Guard said. They were being taken to Italian ports. Hundreds were also rescued Saturday.

Italian Premier Matteo Renzi is pressing for U.N. intervention to stem the violence in Libya.