SAN LEANDRO -- Police are crediting a group of good Samaritans for pulling a 7-year-old boy from the water at the San Leandro Marina and likely saving his life Sunday afternoon.

The boy, however, was in critical condtion at UCSF Benioff Children's Hospital Oakland Sunday night, said Alameda County Fire Department spokeswoman Aisha Knowles.

The boy was reported "in distress" in the water near the Tot Town playground at the marina at 4:19 p.m. Sunday. Authorities said the boy was either swimming or walking in water that he believed to be very shallow, but the water was deeper than was safe for him.

He was underwater approximately 1 minute, said Knowles.

Police received numerous 911 calls reporting the incident and when officers, firefighters and paramedics responded, good Samaritans at the park had already pulled the boy from the water and begun CPR, police said. Police did not say who had been watching the boy before he went into the water or if anyone was cited.

No arrests were made.

Police said the boy was unconscious but that the CPR "likely saved his life."

Police are continuing their investigation and interviewing witnesses but do not suspect foul play.

"If it weren't for observant people in the park and their swift actions, the outcome of (Sunday's) incident may have been drastically different," said Lt. Robert McManus.

Anyone with additional information about this case should call 510-577-3230 or contact the anonymous tip line at 510-577-3278.

Contact Kristin J. Bender at kbender@bayareanewsgroup.com. Follow her at Twitter.com/kjbender.