North American stock markets slid amid slumping commodities prices and concerns stoked by U.S. President Donald Trump about the pharmaceutical industry.

Trump said in a tweet on Tuesday that he plans on implementing a “new system” to bring drug prices lower. It was the first time he has mentioned how he plans on bringing more competition into the drug industry, a sector he has criticized in the past.

The comment sent drugmaker stocks lower on both sides of the border.

In Toronto, the S&P/TSX composite index lost 20.97 points to 15,608.78 with health-care stocks incurring the biggest sector losses, with metals and materials companies also dragging down the commodities-heavy index.

On Wall Street, the Dow Jones industrial average fell by 29.58 points to 20,924.76, the S&P 500 composite index shed 6.92 points to 2,368.39, and the Nasdaq composite index pulled back 15.25 points to 5,833.93.

Investors still remain nervous about what will eventually shake out from Trump’s policies, says Todd Mattina, chief economist and strategist with Mackenzie Financial Corp.

“There’s a lot of uncertainty about Donald Trump’s economic program and these tweets are taken as a signal about what his potential policy priorities will be,” he says.

Shares in several U.S. hospital operators also fell sharply after Republicans announced Monday a health-care proposal to replace the Affordable Care Act, more commonly known as Obamacare. This was third loss in four days for U.S. stocks.

Trading has been tepid across U.S. markets as investors look ahead to Friday’s U.S. jobs report for February.

If the data meet expectations or exceed them, it will be an indication that the U.S. economy is continuing to strengthen and will give the U.S. Federal Reserve Board even more reason to raise interest rates at its meeting next week.

A strong jobs report will also be an important gauge of how the economy has fared in the first full month under the Trump administration. Trump was elected on promises of robust economic growth and job creation.

Markets have priced in a 98% chance that the Fed will hike rates next week, especially if it still plans on following a schedule of three raises this year, Mattina says.

The U.S. central bank has been hinting in the past few weeks that it’s ready to make a move.

“The Fed’s usual strategy is to avoid surprises,” Mattina said.

In currencies, the Canadian dollar declined by US0.03¢ to US74.54¢.

Meanwhile, commodities were negative across the board, as the April crude contract dipped by US6¢ to US$53.14 a barrel and April natural gas contracts were down US8¢ at US$2.82 per mmBTU.

The April gold contract fell by US$9.40 at US$1,216.10 an ounce and May copper contracts were down by US3¢ to US$2.62 a pound.