SAN DIEGO -- One of the nation's largest military bases is reportedly under tighter security after three Middle Eastern men tried to enter without proper authorization.

10News learned the three men -- 40-year-old Afghani Ahmad Rahmani Naeem, 41-year-old Iranian Vahik Petrossian and 27-year-old Iranian Sengekdi Norvik Avanosian -- attempted to get into Camp Pendleton last weekend under what was considered suspicious circumstances.

On Wednesday, base officials said there was no threat, but others on the base told 10News security has been stepped up.

According to a Be On the Lookout (BOLO) alert issued to high-ranking Camp Pendleton officials, someone reported hearing hateful comments and terrorist threats from three men at a gas station in Oceanside Saturday.

Investigators at Camp Pendleton said the men asked the attendant for directions on how to get to Camp Pendleton before they left the gas station.

According to the alert, shortly after midnight Sunday, a rented silver Toyota Corolla driven by Naeem attempted to enter Camp Pendleton through the main gate. As it was being searched, Petrossian and Avanosian drove up in a black Mercedes, but were told to wait. Instead, they continued past the gate and onto the base. Following a short pursuit, the Mercedes was stopped and searched.

No weapons or contraband were found in the Mercedes, but base security noticed the air bag in the steering wheel of the Mercedes had been pulled out and re-attached with duct tape and had wires hanging free, the alert said.

According to the alert, Naaem told base security he was lost and was trying to go to Glendale. When interviewed, Petrossian and Avanosian said they were lost and trying to go to Glendale. The three men claimed not to know each other, the alert said.

Naaem, Petrossian and Avanosian were photographed and released after questioning, and a warning about the trio was posted to law enforcement.

However, later that morning about 8:30 a.m., Naeem returned in the Toyota and tried to get on the base again, saying he made a mistake and was trying to enter Interstate 5, the alert said. After his vehicle was searched, Naeem was issued a letter of debarment from the base and escorted to the freeway.

Since the incident, 10News learned high-ranking Camp Pendleton officials have notified other military bases and law enforcement of a potential threat.

According to a local security expert, that comes with good reason.

"I think after 9/11, anybody on any government facility should be worried," local expert John told 10News.

John, who does undercover security and anti-terrorism work for Eagle Eye Security Solutions, did not want to be identified.

He told 10News the Camp Pendleton incident sounds like a possible probe or dry run and said their visits raise a few red flags.

"Number one: they went on base twice. Their stories didn't stick, kinda wishy washy. Number two: the vehicle, the condition of the vehicle," said John. "They could have been probing the security, not just cameras, sensors, individual security from MPs. Three: [they] could have wanted to know what background checks would have produced."

A criminal background check on the trio conducted by the Department of Homeland Security found no "derogatory records" for the men. Additionally, the U.S. Border Patrol said the immigration statuses for the three men were confirmed and they did not appear on any terrorist watch databases.

Former High-Ranking Marine Reacts To Security Alert

Retired Lt. Col. Thomas Richards, who has seen many BOLO notifications during his service, told 10News, "BOLOS are fairly common. This has significance because Middle Eastern people were trying to get on a U.S. military active base."

Richards said the base holds many targets.

"They could have done a lot of damage ... to people, equipment, the base itself. There’s the Camp Pendleton airfield, lots of helicopters there, any number of barracks, repair facilities, industrial buildings, the Camp Pendleton Naval Hospital," Richards said.

He said the incidents may be a coincidence, but the military can't take a risk.

"It could have been an intelligence reconnaissance mission for them to look around the base and see what there is there to do damage to," said Richards.

Camp Pendleton base officials issued a statement, saying in part: "After further investigation, it was determined that the individuals involved were not a threat to MCB Camp Pendleton or any other military installation in the area. MCB Camp Pendleton officials are not investigating these incidents further."