The Trump administration is continuing its talks with trading partners despite a U.S. appeals court ruling that most of President Donald Trump's tariffs are illegal, U.S. Trade Representative Jamieson Greer said on Sunday.

"Our trading partners, they continue to work very closely with us on negotiations," he said in an interview on Fox News' "Fox & Friends" program. "People are moving forward with their deals, regardless of what this court may say in the interim."

Greer did not say which countries the United States was still in talks with, but said he had spoken with one trade minister on Saturday morning.

The U.S. Court of Appeals for the Federal Circuit in Washington's 7-4 decision on Friday addressed Trump's so-called reciprocal tariffs set in April as well as tariffs imposed against China, Canada and Mexico in February, but does not impact those issued under other legal authority.

Trump blasted the decision and said he would take the case to the U.S. Supreme Court. The appeals court said his tariffs can remain in effect through October 14 to allow for appeals.

The Republican president has made tariffs a pillar of U.S. foreign policy in his second term since taking office in January, using them to exert political pressure and renegotiate trade deals even as the tariffs have increased volatility in financial markets.