A 60-year-old woman died and several others including a rabbi were wounded when a gunman opened fire at a synagogue in a California town Saturday. The motive behind the shooting was not known but authorities described it as a possible hate crime. 

The 19-year-old suspect in the shooting at the Congregation Chabad in Poway, north of San Diego, is in police custody. San Diego County Sheriff Bill Gore identified him as John Earnest, of San Diego, and authorities say they believe he acted alone. 

Reports said Earnest published an anti-Semitic open letter of his white-supremacist views on the anonymous message board 8chan before the shooting, similar to the manifesto published by the Christchurch attack suspect Brenton Tarrant. In the letter, Earnest also reportedly claimed responsibility for an attempted arson at a mosque in nearby Escondido in March.

Congregation Chabad - Synagogue Shooting The exterior of the Congregation Chabad synagogue, where a gunman opened fire killing one person and injuring several others, is seen on April 27, 2019, in Poway, California. Photo: David McNew/Getty Images

President Trump expressed his sympathis to the victims in a tweet. "Thoughts and prayers to all of those affected by the shooting at the Synagogue in Poway, California. God bless you all. Suspect apprehended. Law enforcement did outstanding job. Thank you!"

The suspect was armed with an AR-type assault weapon, reports said, adding he fled the scene possibly because his gun jammed. An off-duty Border Patrol agent fired at the shooter as he fled and is thought to have hit the suspect's car. The suspect then called 911, said he was involved in the shooting and gave his location. He surrendered to a K-9 officer who responded. Earnest is being interviewed by the FBI and detectives.

Of those injured in the shooting, the woman died at the Palomar Medical Center Poway. Three others were also brought to the hospital, one of whom is the 57-year-old rabbi. One of the injured, a girl, was later transferred to a children's hospital.

CNN quoted the wife of a congregation member who had witnessed the shooting as saying that the rabbi, who was wounded, tried to calm the gunman and the congregation. He also called for unity and prayed for peace even after getting shot.

The report further said six or seven shots were fired and the gunman was "cursing when he opened fire." The attack happened around 11.30 a.m. on the last day of the Passover and there were about 100 people in the synagogue.

In October last year, 11 people were killed and six others injured when a a gunman opened fire inside the Tree Of Life synagogue in Pittsburgh, Pennsylvania.

Anti-Semitism is on the rise in the U.S., according to the Anti-Defamation League (ADL). Anti-Semitic incidents increased 57 percent 2017 from the previous year. Messages like "Hitler was not wrong," "Kill all Jews" and "No Jews" have appeared on synagogues, Jewish graves and homes and school campuses.