President Donald Trump imposed the tariffs during the contentious trade talks by using a section of US trade law that allows the president to tax imports on national-security grounds.
Following her meeting with Mr Lighthizer, she repeated the demand that the tariffs - 25 per cent on steel and 10 per cent on aluminum - be withdrawn before the implementing the revised deal known as the US-Mexico-Canada Agreement.
"I think we are close to an understanding with Mexico and Canada", Mnuchin said during testimony on the Treasury Department's budget.
On Wednesday, Freeland will travel to Washington to press for a lifting of the tariffs in meetings with officials including US Trade Representative Robert Lighthizer and Senator Chuck Grassley.
American Treasury Secretary Steven Mnuchin announced earlier today while testifying in front of the U.S. Senate appropriations subcommittee that crippling steel and aluminum tariffs on Canada and Mexico could be over very soon.
Mnuchin acknowledged to the senators what business leaders in all three countries, as well as US lawmakers on both sides of the political divide, have been saying: that the tariffs must be lifted for the newly negotiated North American free trade deal to be ratified by legislators.
"My sense is that we're making progress but there's obviously more work to be done", Finance Minister Bill Morneau said of the tariff situation in Ottawa Wednesday. He not provide any details about the potential agreement.
"I've spoken to the finance ministers", he said.
U.S. Trade Representative Robert Lighthizer enters his vehicle as he leaves from the U.S. Capitol House carriage entrance after a meeting with Speaker of the House Nancy Pelosi at the Capitol in Washington, U.S., May 15, 2019. "It's not necessary because I think the top priority is to get a deal first".
But hostilities resumed last week when the United States accused China of backsliding on major commitments already made in the talks and President Donald Trump more than doubled duty rates on $200 billion in Chinese merchandise imports.
China responded in kind on Monday, raising duties on US$60 billion in United States exports. "I wouldn't say I'm confident", Mnuchin added.
"My expectation is that we will go to Beijing at some point in the near future to continue those discussions", he said.