A former U.S. Marine’s alleged plan to for a holiday attack on Pier 39 in San Francisco has been foiled after he discussed the plan with an undercover FBI agent.

According to an affidavit filed in U.S. District Court in California on Friday, Everitt Aaron Jameson was inspired by the Islamic State.

The 26-year-old from Modesto, Calif., was arrested and charged with attempting to provide material support to a foreign terrorist organization, the the Department of Justice said in a news release Friday.

San Francisco acting Mayor London Breed said in a statement there are no additional known threats to the city, but police will increase their presence.

According to court documents, the FBI began watching Jameson after he had interactions online with an undercover agent in which he expressed support for the Oct. 31 terrorist attack in New York City.

At one point when he met with an undercover agent, he thought he was meeting with senior leadership of ISIS, and offered to carry out an attack and to provide money on behalf of the terrorist organization.

The affidavit shows Jameson served with the Marines in 2009 and had a sharpshooter rifle qualification. He had been discharged for fraudulent enlistment after it was discovered he failed to disclose his asthma history.

Authorities found firearms, empty magazines, ammunition, and fireworks in his Modesto home during a Dec. 20 search.

Jameson remains in custody after appearing in court Friday for a first appearance. He is scheduled for a detention hearing Dec. 28 and a preliminary hearing Jan. 5, and if convicted, he could be sentenced to 20 years in prison and fined $250,000.