(Reuters) - The U.S. Coast Guard has repatriated 97 Cuban migrants picked up at sea, part of a surge in attempts to reach the United States from the Communist-run island, the service said on Saturday.

The Cubans were sent back to the Caribbean nation since last Sunday and carried aboard three cutters, the Coast Guard said in a statement. The Cubans had been picked up in seven interdictions at sea.

“We discourage anyone from taking to the sea and attempting to reach U.S. soil illegally – they are risking their lives with very little chance of success,” said Captain Mark Gordon, chief of enforcement for the Coast Guard’s 7th District.

The number of Cuban migrants trying to reach the southeastern United State last month was 834, up from 410 in July 2015, the statement said.

Since Oct. 1, at least 5,786 Cubans have tried to migrate to the United States by sea, compared with 4,473 in federal fiscal year 2015.