The New York attorney general, Andrew M. Cuomo, sued two large debt settlement companies Tuesday, saying they had engaged in fraudulent and deceptive business practices and false advertising.

The suits seek to enjoin the companies, Nationwide Asset Services and Credit Solutions of America, from many of their business practices, including charging customers before any settlement work is done. They also seek restitution and damages for dissatisfied customers.

“These companies claim to be the light at the end of the tunnel, but time after time they have shown that they only add to the burdens of Americans dealing with debt,” Mr. Cuomo said in a statement.

Credit Solutions enrolled 18,000 customers in New York State in the last five years, earning $17 million in fees, but settled the debts of fewer than 2,000 of them, the attorney general said.