DETROIT (AP) – The top negotiator in contract talks between General Motors and the United Auto Workers says bargaining has hit a big snag.

In an email to union members, UAW Vice President Terry Dittes casts doubt on whether there will be a settlement soon in a dispute that’s led to a 21-day strike by 49,000 union members.

Dittes’ letter says the union presented a proposal to the company Saturday. He says GM responded Sunday by reverting back to an offer that had been rejected and made few changes.

He says the company isn’t willing to fairly compensate workers.

GM says it continues to negotiate in good faith “with very good proposals.”

The strike has shut down GM’s U.S. production since Sept. 16 and hampered manufacturing in Mexico and Canada.