Shares in US-listed steel companies rose sharply late on Thursday after Donald Trump accused China of dumping cheap steel in the American market and was considering imposing both tariffs and quotas on imports.
The rally was part of a longer-run increase for the industry, which has been awaiting a US Department of Commerce report that is expected to find underpriced imports poses a national security threat.
On Air Force One en route to Paris for a presidential visit, Mr Trump told reporters China and other countries were "dumping steel [in the US] and destroying our steel industry", adding: "They've been doing it for decades and I'm stopping it. It'll stop.
"There are two ways: quotas and tariffs. Maybe I'll do both. We're like a dumping ground, OK?"
The comments by Mr Trump were initially off the record and not reported by journalists travelling with the president, who was on his way to Paris to attend Bastille Day festivities. However, the White House later changed the ground rules and released a transcript of his remarks, sparking the steel rally. AK Steel, a Pittsburgh-based producer, closed 7.1 per cent higher, while US Steel, the largest domestically based US steel producer, rose 3.8 per cent. Nucor, the largest mini-mill steelmaker, gained 2.7 per cent, ArcelorMittal was up 2.1 per cent and Steel Dynamics jumped 2.3 per cent.
Nonetheless, share prices in the sector remain off their peaks from earlier in the year, as investors' optimism over the Trump administration's policy agenda has faded. The commerce department steel report was due at the end of June, and investors have grown concerned Mr Trump may not move forward with his threat of tariffs.
On Thursday, Wilbur Ross, the commerce secretary, told members of the Senate Finance Committee that he would present Mr Trump with the options for potential action as early as next week.
Several agricultural lobby groups have signed a joint letter to Mr Ross, claiming any restrictions on steel or aluminium imports could lead to other countries retaliating by restricting imports of agricultural products from the US.
"If the . . . investigations on steel and aluminium result in new trade barriers, the aftermath could be disastrous for the global trading system and for US agriculture in particular," the letter read.
Mr Trump was asked on the flight whether he would use trade as a bargaining chip with China over its relationship with North Korea.
"The biggest strength we have are these horrendous trade deals, like with China," he said. "That's our strength. But we're going to fix them. But in terms of North Korea, our strength is trade."