President Trump imposed steep tariffs on steel and aluminum imports on Thursday, singling out China as a top offender in an effort to curb what he has called unfair trade practices. But there is little evidence to support his dismissal of estimates that say Chinese steel accounts for only a small percentage of imports into the United States.

We fact-checked Mr. Trump’s targeting of China’s trade practices this week.

“Transshipping, frankly, is a big deal. China says it’s got 2 percent, but it sends much more.” — March 8

This lacks evidence.

Mr. Trump repeated this claim as he prepared to announce the tariffs. “I’ve watched where the reporters have been writing, 2 percent of our steel comes from China. Well, that’s not right,” Mr. Trump said at a news conference on Tuesday. “They transship all through other countries.”

“They send us a much, much higher level than that, but it’s called transshipping,” he added.

Transshipping refers to a practice in which one country exports a product to another country after it passes it through a third country. It is illegal when done to falsify or disguise the product’s country of origin and to evade duties and tariffs.

There is little evidence to support Mr. Trump’s claim that the volume of Chinese steel imports is “much higher” after transshipping.