Trade negotiators from Canada, Mexico and the United States resume discussions on Friday over the future of the North American Free Trade Agreement.

The first round of the talks, which opened in Washington last month, got off to a tense start with the Trump administration admonishing its neighbors and declaring that Nafta had “fundamentally failed.”

As the second round gets underway in Mexico City, the three countries said in a statement that they were committed to an “ambitious outcome.”

What is being negotiated?

Nafta, which came into force in 1994, created what is now the world’s biggest free-trade bloc.

But the pact has been the focus of criticism in recent years. Opponents in the United States — President Trump chief among them — argue that it has allowed Mexico to benefit at the expense of its neighbor to the north.