Mexico called on the U.S. to modify legislation under which it would send so-called labor attaches to monitor enforcement of USMCA trade deal rules, saying that it wasn’t consulted.

If it doesn’t, Mexico said it will no longer consult the U.S. when it drafts its own implementation rules, Foreign Affairs Minister Marcelo Ebrard said.

A showdown is escalating between the two countries over a bill in the U.S. Congress about implementation of the USMCA, or United States-Mexico-Canada Agreement. The bill authorizes up to five labor attaches to ensure that its southern neighbor guarantees workers their right to union representation.

Enforcement of union rights is has been a key priority for Democrats in the U.S. Congress.

Mexico will decide whether it authorizes U.S. labor attaches to operate in its country, after meetings today between U.S. and Mexico negotiators, Ebrard said. He said he also wants to meet with U.S. Secretary of State Mike Pompeo on the matter.

In any event, attaches wouldn’t be allowed to visit establishments in Mexico to monitor labor activity, he said.Deputy foreign minister Jesus Seade criticized the U.S. for not consulting Mexico on the question of the attaches and is meeting with U.S. officials today to discuss it.

“Very politely, we will say that we won’t consult them in implementing laws if they don’t modify this,” Ebrard said. “Equal treatment, full reciprocity.”Ebrard said the USMCA accord isn’t at risk over the dispute.