(Adds details, Navarro, Bolten and Graham comments)
WASHINGTON, March 4 (Reuters) - U.S. President Donald Trump has spoken to multiple world leaders about tariff hikes on steel and aluminum but still has no plans for exemptions, Commerce Secretary Wilbur Ross said on Sunday, but he would not rule out the prospect.
In appearances on U.S. television news shows, Ross sought to contain the global fallout from Trump's tariff announcement, insisting the proposals would not hurt the U.S. economy and playing down the effects of any retaliatory strikes.
Trump said on Thursday the United States would impose duties of 25 percent on imported steel and 10 percent on aluminum this week to protect domestic producers.
Ross said Trump has had conversations with a number of world leaders since the announcement, which stunned U.S. trading partners, alarmed American industry leaders and roiled stock markets.
There was no indication Trump was considering lower tariffs or exemptions for any countries, Ross said.
Numerous ministers from around the world have been in touch with Trump and administration officials including Ross, hinting at an intensive behind-the-scenes effort to change the U.S. president's mind, the commerce secretary said.
Ross did not rule out that possibility.
"We shall see, we shall see. I know that a lot of ministers from a lot of countries have been talking with the president. They've been talking with me. They've been talking with others," he said on NBC's "Meet the Press" program "We'll see. The president makes the decision."
Canada, the biggest steel supplier to the United States, is trying to secure an exemption from potential U.S. tariffs on steel and has threatened retaliation if the plan goes ahead.
Peter Navarro, director of the White House National Trade Council, said exempting countries was a slippery slope.
"There will be an exemption procedure for particular cases where we need to have exemptions, so that business can move forward. But at this point in time there will be no country exclusions," Navarro said, without elaborating.
"If you exempt Canada, then you have to put big, big tariffs on everybody else," he said on CNN's "State of the Union" program.
Ross played down the effects of the proposed tariffs on the U.S. economy. saying they represent a fraction of 1 percent of the economy. "So the notion that it would destroy a lot of jobs, raise prices, disrupt things, is wrong," Ross told ABC's "This Week" program.
The commerce secretary dismissed European Union threats of retaliatory tariffs on flagship American products, including Harley Davidson motorcycles, bourbon and Levi's jeans, which he said amounted to about $3 billion and were seen as "pretty trivial" and a "rounding error."
On Saturday, Trump threatened European automakers with a tax on imports if the European Union retaliates.
A number of Trump's fellow Republicans, including congressional leaders, have urged him to hold back on the tariffs.
Josh Bolten, chief executive officer of the influential Business Roundtable and former chief of staff to President George W. Bush, described the tariffs as "a huge mistake" on the "Fox News Sunday" program.
"This will cause huge damage across broad sectors of the economy," he said. "You maybe will be able to give a little bit of help to the steel and aluminum industries. Youre going to cause damage across any number of downstream industries.
Bolten said he agrees that the overproduction of steel by China has harmed U.S. steel makers and cost jobs, and stressed that Trumps proposed tariffs would not tackle the problem as China accounts for only 2 percent of U.S. steel imports.
"You are letting China off the hook. China wins when we are fighting with Europe," Republican Senator Lindsey Graham said on Fox. (Reporting by Doina Chiacu, Valerie Volcovici and Sarah N. Lynch in Washington Editing by Alexander Smith and Jeffrey Benkoe)