Around 8 a.m. this morning, U.S. Coast Guard officials suspended a search for the source of emergency flares that were seen in the San Joaquin River in Contra Costa County.

At 1:30 a.m. Saturday, a red flare was reported in the river around the Antioch Bridge, Petty Officer Laura Alcon said. A Coast Guard boat and helicopter searched for hours until 3:30 a.m., two additional red flares were seen, she said.

The helicopter was sent out again at sunrise, 6:11 a.m., today and the search area was increased to waters near Sherman Island, but Coast Guard officials didn't find anything, Alcon said.

The search was suspended just before 8 a.m.

Boats are required to have flares in emergency kits onboard, red and orange flares are used to signify distress, Alcon said.