Argentina's government is again rejecting negotiations with a group of hedge funds that hold some of the government's bonds, arguing that the U.S.-led group has created a tense environment by harassing the South American nation.

In a letter dated Monday, the law firm representing Argentina in the United States said Argentina also lacks confidence in appointed mediator Daniel Pollack.

The dispute has its roots in Argentina's $100 billion default in 2001. Most creditors renegotiated the debt in 2005 and 2010 bond swaps. But a group of creditors refused and took Argentina to court in New York.

Judge Thomas Griesa has repeatedly ruled that Argentina can't make payments on its debt without paying the holdout funds. Argentina rejects that, and the holdout funds have tried to seize Argentine assets overseas.