Raymond Davis, the CIA contractor whose arrest in Pakistan for killing two men strained Islamabad-Washington ties, was on Monday formally charged with felony assault after his weekend arrest for fighting over a parking spot in midwestern state of Colorado, according to media reports.

Davis, 37, appeared briefly before a magistrate judge in Douglas County Monday morning, where his attorney said his client was prepared to plead guilty to a misdemeanor charge, The Denver Post reported on its web site.

But Senior Deputy District Attorney Rich Orman said his office planned to upgrade the charges to a felony, to better reflect the seriousness of the crime, it said.

Later, the Judicial District Attorney's Office formally charged Davis with 2nd-degree assault, a felony, in addition to an earlier misdemeanor charge of disorderly conduct, according to the Post.

The assault charge, which includes a violent crime count, has a mandatory minimum sentence of five years in prison and a maximum sentence of 16 years.

The charges stem from an altercation Saturday morning outside a bagel shop at the TownCenter in Highlands Ranch.

According to the Douglas County Sheriff's Office, Davis and another man began arguing with a 50-year-old man about a parking space when things turned physical.

Davis was arrested and charged with third-degree assault and disorderly conduct, both misdemeanors. He posted $1750 bond and was released.

Davis grabbed headlines in January, while working as a contractor in Lahore he shot and killed two men he claimed were trying to rob him.

After his arrest, US officials said Davis should be released because he carried a diplomatic passport and was protected under diplomatic immunity.

Davis was eventually freed in March after, in accordance with an Islamic law, the victim's families granted him a pardon in exchange for $2.34 million in compensation.

It was later revealed that Davis was a former member of the US Special Forces and was employed by the private security firm Blackwater.

He reportedly owns a security company called Hyperion Protective Consultants, which is contracted to do work for the government.

Davis did not speak during Monday morning's appearance or on his way in or out of the courtroom.

His attorney, William Frankfurt, told Magistrate Judge Frank Moschetti he wanted to address a condition of a mandatory protection order that prohibits Davis from carrying a firearm. But Moschetti said he wasn't inclined to do so, "especially given the nature of the allegations in this case."

Davis is scheduled to appear in court again Tuesday.