JPMorgan Chase & Co disclosed on Friday that its "criticized" loans to the oil and gas industry more than doubled in the first three months of the year.

Criticized oil and gas loans, which are defined by regulators as doubtful, substandard or deserving of special mention, rose to $9.7 billion at the end of March from $4.5 billion at the end of December, according to a quarterly filing the company made with the U.S. Securities and Exchange Commission.

Of the criticized loans, $8 billion were still performing, according to the filing.

The change in criticized status comes as JPMorgan and other banks have added to reserves for possible loan losses because of the impact on sharply lower oil revenue on the ability of borrowers in the shale oil industry to repay their debts.

A JPMorgan spokesman declined further comment.

JPMorgan said its total exposure to oil and gas and natural gas pipeline industries had risen $1.5 billion to $47.9 billion, or 5.8 percent of total wholesale loans and commitments to lend.

The company said earlier this month that it had some attractive opportunities to make additional loans to the industry.

(Reporting by David Henry in New York; Editing by Chris Reese and Andrew Hay)