WASHINGTON — A person briefed on discussions between the Justice Department and JPMorgan Chase & Co. says negotiations between the government and the bank have hit a stumbling block that has put the talks at risk.

A week and a half ago, JPMorgan tentatively agreed to pay $13 billion to settle allegations surrounding the quality of mortgage-backed securities it sold in the run-up to the 2008 financial crisis.

According to the person familiar with the discussions, the Justice Department says none of the costs the bank pays can be passed on to the Federal Deposit Insurance Corp., the independent agency created by Congress to maintain stability in the banking system. JPMorgan disputes that. The two sides also disagree over whether the bank can face criminal charges. The person spoke on condition of anonymity because the source was not authorized to speak on the record about the matter.