WASHINGTON (AP) — President Donald Trump said Sunday he will extend a deadline to escalate tariffs on Chinese imports, citing "substantial progress" in weekend talks between the two countries.

Trump tweeted that there had been "productive talks," adding that "I will be delaying the U.S. increase in tariffs now scheduled for March 1."

Trump said that if negotiations progress, he will meet with Chinese President Xi Jinping at his Florida resort to finalize an agreement.

U.S. and Chinese negotiators met through the weekend as they seek to resolve a trade war that's rattled financial markets.

Trump had warned he would escalate the tariffs he has imposed on $200 billion in Chinese imports, from 10 to 25 percent, if the two sides failed to reach a deal. The increase was scheduled to take effect at 12:01 a.m. EST on March 2.

The world's two biggest economies have been locked in a conflict over U.S. allegations that China steals technology and forces foreign companies to hand over trade secrets in an aggressive push to challenge American technological dominance.

The two counties have slapped import taxes on hundreds of billions of dollars of each other's goods. The conflict has shaken financial markets and clouded the outlook for the global economy, putting pressure on Trump and Xi to reach a deal.

"Trump clearly wants a deal and so do the Chinese, which certainly raises the probability that the two sides will come to some sort of negotiated agreement, even if it is a partial one, in the coming weeks," said Cornell University economist Eswar Prasad, former head of the International Monetary Fund's China division.

But business groups and lawmakers in Congress want to see a comprehensive deal that forces the Chinese to change their behavior and can be enforced.