(L-R) Canadian Foreign Affairs Minister Chrystia Freeland, U.S. Trade Rep Robert Lighthizer and Mexican Secretary of Economy Ildefonso Guajardo Villarreal arrive at a joint news conference after a NAFTA trilateral ministerial press event in Washington, October 17, 2017.

Ministers from the United States, Canada, and Mexico meet on Monday to wrap up the latest round of NAFTA talks under the shadow of U.S. President Donald Trump's proposed steep tariffs on steel and aluminum imports.

Trump is expected to finalize the tariffs — 25 percent on steel and 10 percent on aluminum — later in the week, posing a tough challenge for U.S. Trade Representative Robert Lighthizer, Canada's Foreign Minister Chrystia Freeland, and Mexican Economy Minister Ildefonso Guajardo.

The Mexican and Canadian ministers are likely to press Trump's trade envoy on whether their countries will be excluded from the blanket tariffs.

"I expect it to be front and center" at the meeting, said Kevin Brady, the Republican chairman of the U.S. House of Representatives Ways and Means Committee, which oversees U.S. trade policy.

Officials have so far been evasive when asked how the three nations can continue trying to update the North American Free Trade Agreement at a time when the U.S. president is about to take a highly protectionist measure.

Brady led a delegation of U.S. lawmakers to Mexico City to press officials on the need to conclude the talks, which have unnerved financial markets worried about the possibility that the North American supply chain could be disrupted.

Speaking on Sunday, Brady said all fairly-traded steel should be excluded from the tariffs. U.S. stocks fell sharply on Thursday on fears of a looming trade war after Trump, a Republican, announced the planned tariffs.