(Reuters) -The tariffs U.S. President Donald Trump imposed last week on scores of countries are likely to stay in place rather than be cut as part of continuing negotiations, Trade Representative Jamieson Greer said on Sunday.

Ahead of a Friday deadline, Trump set rates including a 35% duty on many goods from Canada, 50% for Brazil, 25% for India, 20% for Taiwan and 39% for Switzerland, according to a presidential executive order.

In trade talks since Trump returned to office, the White House has lowered some rates from levels initially announced, including halving import duties set last week as part of a deal with the European Union.

Greer told CBS's Face the Nation on Sunday, however, that this would not be the case on the most recent round of tariffs.

"A lot of these are set rates pursuant to deals. Some of these deals are announced, some are not, others depend on the level of the trade deficit or surplus we may have with the country," he said. "These tariff rates are pretty much set."

Greer also said recent trade talks with Beijing had been "very positive" and were focused on the supply of rare earth magnets and minerals.

"We're focused on making sure that the flow of magnets from China to the United States and the- and the adjacent supply chain can flow as freely as it did before ... and I'd say we're about halfway there."