Honolulu firefighters and lifeguards were searching by sea and air Saturday afternoon for two people missing in the ocean off East Oahu.

Honolulu Fire Department spokesman Kendall Ching said firefighters responded to a report of two adult swimmers in distress about 5 p.m. in an area off Halona Blowhole.

He said a third person saw the two people in trouble and went into the water with a surfboard but had to be rescued by lifeguards after he began struggling in the water.

A surf advisory is in effect for south shores across the state and is keeping emergency responders busy with ocean rescues this weekend.

Lifeguards made 21 rescues on the south shore and 18 rescues on the west side by 4:45 p.m. Saturday, according to a Honolulu Emergency Services spokeswoman. Lifeguards also made 3,000 preventative actions on south and west shores.

In a separate incident on Saturday, firefighters responded to a boat in distress off Diamond Head and towed the vessel back to Ala Wai Boat Harbor about 4 p.m., Ching said.

At about 6:30 p.m., firefighters were still searching for the swimmers off Halona Blowhole until nightfall, Ching said.

About the same time, lifeguards and firefighters were responding to several swimmers in distress off Makaha.