The death toll in Friday's deadly plane crash at the Nevada Reno air race has climbed to 9, including the pilot, local news quoted police as saying Saturday. More than 50 others were injured.

Whether the death toll would further increase was uncertain. Investigators are still examining the site. National Transportation Safety Board has sent a team from Washington to join regional officials for the investigation. The cause of the accident was still unknown.

Earlier in the day, the Renown Regional Medical Center announced two people injured in the crash have died overnight. Six are in critical condition and another two are seriously wounded.

On Friday, a World War II fighter aircraft P 51 mustang flown by veteran pilot Jimmy Leeward lost control and plunged into the grandstand at Reno National Championship Air Races, the worst accident in the history of the 48-year-old event.

After the crash, Mike Houghton, president and chief executive officer of the Reno Air Races, told a broadcast press conference that there were a total of 54 injuries, all having been transported to local hospitals for treatment. Houghton called the accident "a mass casualty situation." He said the cause was still under investigation but appeared to have been mechanical.

This was the first time there has been a crash with live spectators. The grandstand holds 10,000 people, and there were 7, 500 people in attendance, local news said. Air races have been canceled for the weekend.

74-year-old Leeward was a well-known air racing pilot from Florida. Witnesses said they had seen Leeward having tried to pull back before his plane hit down, which saved a lot of lives. Houghon said the plane was "flying on course" and Leeward appeared to have "lost control of the aircraft."

Videos of the crash showed that the plane climbed vertically in the air and then suddenly dropped down at about 4:30 p.m. local time on Friday during the popular annual air show, leaving audiences running for their life while wreckage scattered.

Right after the crash, Stephanie Kruse, spokeswoman for the Regional Emergency Medical Service Authority, said 25 people were critically injured and another 25 people were seriously injured in the crash. She added that the critically injured were considered to have life-threatening injuries.

Local TV said the Reno Air Racing Association is planning a public memorial for the victims in the tragedy.

Leeward was a well-known air racing pilot. His Facebook page showed that he started participating in air races in 1970s and owned the Leeward Air Ranch Racing Team and had flown over 120 races. Leeward had also been involved in numerous movie stunts, such as Amelia, Cloud Dancer, Tuskegee Airmen and others.

The National Championship Air Races, which began in the mid- 1960s, draws thousands of people every year in September to watch various military and civilian planes race. Four pilots were killed in 2007 and 2008 air races. Friday's tragedy again has raised safety concerns over such events.