Nearly 40 people were arrested in a 24-hour period as a result of three maritime human smuggling incidents along the Southern California coast, officials said Friday.

The events occurred on Oct. 27 and 28..

On Oct. 27 at 9:30 a.m., federal agents observed four people being dropped off from a fishing vessel at Dana Landing in Mission Bay, officials said. Agents approached the group and conducted an immigration inspection and determined they were in the country illegally, officials said.

The four were arrested, along with the vessel’s captain, a crew member and another person suspected of attempting to pick up the group in an awaiting vehicle.

Later, federal agents encountered 16 people who abandoned a beached pleasure craft near Crystal Cove in Newport Beach.

“Smugglers consistently put migrants at risk, with disregard for their safety,” Brandon J. Tucker, director of Customs and Border Protection’s San Diego Air and Marine Operations, said in a statement. “The ocean is one of the most dangerous routes to attempt illegal entry into the United States.”

On Monday around 3 a.m., federal agents spotted a suspicious vessel 3 miles off the coast of Solana Beach. About an hour later, agents saw a group of people getting off the panga boat near Beacons Beach in Leucadia, officials said.

After a search, agents found 15 people illegally in the U.S. — all were transported to a Border Patrol station, while the captain was able to flee with the panga south into Mexican waters, officials said.