Three people were killed and 23 others were transported to a nearby hospital after a wooden boat capsized off the coast of San Diego Sunday morning, CNN reports.

San Diego Fire Rescue Department spokesperson Monica Munoz said three people who were hospitalized are considered to be in “somewhat to very urgent status,” while the others are deemed “non-emergent.” 

The incident was first reported around 10:30 a.m. when Customs and Border Patrol officials believe the vessel overturned after crashing into the shoreline surrounding the Cabrillo National Monument. Jose Ysea, spokesperson for the City of San Diego, told KWQC that when they got to the scene, there was a “large debris field” of broken wood and other items, hinting at what may have occurred hours before they had arrived. “In that area of Point Loma it’s very rocky. It’s likely the waves just kept pounding the boat, breaking it apart,” Ysea said. 

San Diego firefighters and lifeguards were assisted by federal firefighters, the U.S. Coast Guard and other local agencies in the rescue efforts. Federal agencies stuck around searching “in vessels and aircraft” for additional survivors, even though they believe everyone has been accounted for. 

Officials suspect the vessel was part of smuggling operation that was transporting undocumented people into the United States.