Asked about the shooting at an unrelated event on Monday, US President Donald Trump calls it a "terrible situation".

"I've been given some early updates but we're going to be going back and looking at it very strongly," he says.

Shaimaa Khalil
Los Angeles Correspondent

Today’s shooting is a massive jolt to a community preparing for one of its holiest seasons and its biggest feasts.

We’re days away from Eid al-Adha or the "Festival of Sacrifice," one of the two major Muslim holidays, where families celebrate and commemorate the obedience of Prophet Ibrahim.

This is a very significant time in the Islamic calendar. We are currently in Dhul-al-Hijjah month, which is the 12th and final month of the Islamic lunar calendar

These days are considered the most sacred, spiritually significant 10 days of the entire year. The first 10 days of Dhul-al-Hijjah are highly revered.

This is the season of the Hajj Pilgrimage – the day of Arafat considered the holiest day of the year.

Image source, Reuters

Imam Taha Hassane of the Islamic Center says "we have never experienced a tragedy like this before".

Speaking over the noise of sirens and helicopters, he says: "It is extremely outrageous to target a place of worship."

"I would like also to thank all the people that contacted us from across the country and overseas, to give condolences and to ask if there is anything they can do to help," he says, also thanking local police and FBI.

The press conference has finished, and police say they will be back in two hours time for another update.

Image source, Getty Images

Image source, Getty Images

The police chief says that the Islamic Center has security services and that one of the deceased "is a security guard that works there".

He also says that a nearby landscaper was shot at, but he was not injured.

Wahl says that scene was "extremely chaotic" and there were somewhere between 50 to 100 police officers at the facility.

There are a total of five people dead, police say.

That includes two suspects and three adult victims at the Islamic Center.

The suspects appear to have died from self-inflicted gunshots wounds, police say.

"There were no officers involved in firing their weapons," Wahl says, adding that it is "still very preliminary at this point".

The suspects are believed to be 17 and 19 years old, he says.

San Diego Mayor Todd Gloria says he is grateful that the children studying at the school when the attack occurred are safe.

"To our local Muslim community my prayers are with you," he continues.

He says he wants to assure the Muslim community that "no resource will be spared" to make sure they are kept safe from violence.

Gloria goes to express his "immense gratitude to law enforcement", and says this is "a tragic situation".

He also send his condolences to the victims, and says investigators will "do everything necessary" to uncover what happened.

"Hate has no place in the city of San Diego," he says.

Image source, Getty Images

Wahl says that the incident at the Islamic Center is currently being treated as a "hate crime" and that police are working closely with the FBI.

FBI special agent Mark Remily is now speaking, saying that there are three deceased adult males who are victims of the shooting.

He adds that two suspects, both of whom were teenagers, are confirmed deceased.

Remily says the FBI is "meticulously" assessing the situation and deploying every resource to uncover the acts of the incident.

He also calls on the public to supply any information that may be able to assist with the investigation.

Two people found dead nearby are believed to be the suspects in the shooting, police say.

Their bodies, both teenagers, were found inside of a vehicle near the mosque, officials say.

"The circumstances that led up to this and the details of what happened - and exactly which time it happened - will come out in days ahead," San Diego Police Chief Scott Wahl says.

"In 28 years this is the most dynamic response and impressive response I have ever seen in policing," he adds.

Police were called to the scene at 11:43 local time, and "observed what appeared to be three deceased victims out front", the police chief says.

More officers arrived within four minutes, he continues.

"At about the same time, we began to receive calls from a couple blocks away of more active gunfire."

Two suspects, both reportedly teenagers, were found dead in a vehicle with self-inflicted wounds, the police chief says.

San Diego Police Chief Scott Wahl is speaking to the media.

He says there is no further threat in the area and two suspects are "deceased".

The police chief adds that there are three adults who died at the Islamic Center.

"Our hearts go out to the families that are in this moment being notified of what has happened to their loved ones," he says.

In the next few minutes we are expecting a statement from San Diego police on the incident.

You can watch live at the top of this page.

Sareen Habeshian
Reporting from California

Sharp Memorial Hospital is receiving patients related to the shooting, a spokesperson for Sharp HealthCare tells the BBC.

"Reports indicate multiple injured people," spokesperson Alicia Cook says.

"Our disaster procedures have been activated and we are coordinating with the County of San Diego and other resources to respond to the incident," Cook adds.

Image source, Reuters

Image source, Getty Images

San Diego Mayor Todd Gloria says the city's police department has advised that there is no ongoing threat to the community.

In a social media post, Gloria thanks emergency services and law enforcement "who responded quickly to protect lives and secure the area".

Witnesses are continuing to describe their experience to CBS, the BBC's US partner.

One woman speaking with CBS says her grandchildren were in the nearby Hebrew school, which also went into lockdown when the shooting happened.

The children are 11 and 13, says the woman. The Hebrew school is located across the street from the Islamic Center of San Diego.

Her granddaughter has been able to text her, sending a message from lockdown saying: "I think we're safe."

Aerial video from the scene showed children holding hands and being escorted through a parking lot of the Islamic Center, which has a school on its campus.

Nearby schools were also placed on lockdown as police responded to the area.

A reunification location was established for parents to meet their children.

Image source, Reuters

The Islamic Center is the largest mosque in San Diego County, with more than 5,000 members in its congregation, according to its website.

The campus includes the Al Rashid School, which offers religion and language courses.

According to its website, the centre's mission is to serve the Muslim population, and also "work with the larger community to serve the less fortunate, to educate, and to better our nation".

A witness speaking to CBS News, the BBC's US partner, says he heard up to 30 gunshots from what sounded like "a semi-automatic weapon".

He said he first heard about a dozen shots, then a pause, then another possibly dozen shots.

The man, who is retired and was eating lunch at home, says he called 911 and that police arrived within "five to 10 minutes".

The mosque gets very busy during holidays, he says.

"It's a good thing it didn't happen on a Friday. Because the streets would be full of people," he says.

San Diego Mayor Todd Gloria said he was "aware of the active shooter situation" at the Islamic center.

"Emergency personnel are on scene and actively working to protect the community and secure the area," he added in a social media post shared around noon local time.

California Governor Gavin Newsom's office said he has been briefed on an "evolving situation".

The Governor’s Office of Emergency Services is coordinating with local law enforcement, they said.

"We are grateful to the first responders on the scene working to protect the community and urge everyone to follow guidance from local authorities," Newsom's office said.