Authorities in California have arrested a man who was seen near a golf course owned by President Donald Trump in the Los Angeles area, ahead of the president's visit for a fundraising dinner there.

Jeanine John Taele, 38, was found with a pistol and illegal ammunition at the Trump National Golf Course in Rancho Palos Verdes, investigators say.

According to the Los Angeles Sheriff's Department, he was "observed walking throughout the golf course grounds taking photographs and videos and appearing to monitor security-planning activities".

The arrest took place on Sunday afternoon. Trump is currently visiting California to attend a Republican party fundraising dinner at the course on Tuesday.

Taele is being held on charges of carrying a concealed firearm and possession of armour-piercing/prohibited ammunition.

In a news release, the sheriff's department said Taele was arrested after plainclothes federal agents reported a suspicious person to local authorities during the middle of the day, around 1530 ET (2330 BST).

When police confronted the man, they discovered that he was being sought in connection to a robbery by the El Segundo Police Department, about 15 miles (25km) north of Rancho Palos Verdes, a wealthy coastal enclave known for its hills and scenic cliffs.

Authorities searched him and found he was carrying a 16-round magazine containing hollow point ammunition. In his vehicle, which was parked at the golf course, they found a loaded pistol, along with a loaded magazine containing hollow-point ammunition.

Hollow point bullets flatten and widen on impact, causing maximum damage to vital organs. California, which has some of the strictest gun laws in the US, has banned magazines capable of holding more than 10 bullets.

The suspect's home in Downey, a city also in the LA-area, was raided on Monday by agents from the FBI's Joint Terrorism Task Force and the LA County Sheriff's Department Major Crimes Bureau.

The sheriff's department said his home was searched due to the "potential security implications surrounding the incident".

Inside his home, they found an "illegally modified AR platform rifle" a .45 pistol, body armour, high-capacity magazines, a plethora of bullets for pistols and rifles and multiple notebooks "containing concerning statements".

The investigation is continuing, with assistance from the US Secret Service, and officials say more charges may be filed later.

The sheriff's statement adds that they have not identified any "credible threat to our communities".

"However, this case underscores the importance of vigilance, strong partnerships with local, state, and federal law enforcement agencies, and the proactive steps taken to identify and investigate suspicious activity before it can escalate."

The arrest happened during a rare visit to California by the president. He is planning to attend a Republican fundraising dinner at his golf course

According to the White House, Trump was due to give a speech critical of California Governor Gavin Newsom, who is widely considered to be planning a run for the presidency in the 2028 election, after Trump's second term ends.

On Wednesday, Trump is travelling to Las Vegas to deliver a speech at a casino.

The visits come as campaign activity ramps up ahead of the mid-term elections in November, when the balance of power in Congress is up for grabs.

Trump has survived three assassination attempts in recent years. After the most recent, when a gunman stormed a hotel in Washington during a White House dinner, Trump's security team said they would review their protocols for protecting the president.

Officials have not said whether the suspect in Rancho Palos Verdes was seeking to hurt Trump and he is not facing any criminal charges related to such allegations. (BBC)

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