A 32-year-old man was arrested and charged after he was pulled over with a pressure cooker and an AR-15 rifle near Chicago's O'Hare International Airport, but his family insists it's all just a misunderstanding.

Santos Zamora appeared in court on Sunday on a felony aggravated unlawful use of a weapon charge, the Chicago Tribune reported.

Police stopped Zamora on Cumberland Road near the Kennedy Expressway around 8am on Saturday for driving 20 mph over the speed limit after leaving the airport, prosecutors say.

An officer noticed that Zamora had a black gun case in the front passenger seat during the traffic stop, according to the police report.

Santos Zamora (above in mugshot), 32, appeared in court on Sunday on a felony aggravated unlawful use of a weapon charge

He was arrested and charged after he was pulled over with a pressure cooker and an AR-15 rifle near the Chicago O'Hare International airport (file above)

The 32-year-old man told the officer that between his feet he had a .45-caliber handgun and an AR-15 rifle in the trunk of the vehicle, according to the police report. Police did not say whether one or both guns found in the vehicle were loaded.

During a search of his 2005 Mitsubishi Galant, officers also found a pressure cooker inside the trunk, court records state.

Police said they found traces of food inside the pressure cooker which helped to dispel concerns that Zamora might have been plotting to use it as a weapon.

Two other people inside the car were detained while the CPD Organized Crime Bureau and Joint Terrorism Task Force were called to conduct an investigation, police said.

Zamora was arrested and also faces several traffic violations for speeding and driving his car without insurance. The incident involving Zamora, who is from Sheboygan, Wisconsin, sparked a counter-terrorism investigation, police say.

Authorities also say he did not have an Illinois Firearm Owners Identification card.

The items were found in his car after police stopped Zamora on Cumberland Road (file above) Saturday for driving 20 mph over the speed limit, prosecutors say. His bond was set at $5,000 by Lyke during the hearing. Zamora's next court appearance is scheduled for Friday

The two other people who were detained were released without charges.

During his court session in front of Cook County Judge John Lyke, his family claimed that the incident was a misunderstanding.

They said that he traveled to Chicago to visit his brother Roberto Zamora.

'We were supposed to go to the gun range,' Gage Park resident Roberto Zamora told the newspaper.

'He wasn't familiar with the law in Illinois. He's been living in Wisconsin.'

Zamora, who is a father and graphic designer, also had plans to visit his newborn nephew, his family claimed.

His bond was set at $5,000 by Lyke during the hearing. Zamora's next court appearance is scheduled for Friday.