NEW YORK (AFP) - US stocks rose on Friday (Aug 25), with petroleum-linked shares lifted by energy outages related to Hurricane Harvey as Federal Reserve Chair Janet Yellen steered clear of monetary policy during her much anticipated address.

The dollar fell sharply against the euro after Yellen, appearing at an annual summit of central bankers in Jackson Hole, Wyoming, avoided monetary policy in remarks that defended tougher regulations on banks.

That absence raised additional doubts on whether the Fed will go ahead with a third interest rate increase in 2017 after two earlier hikes.

A weak dollar is considered mostly positive for US stocks because it boosts profits for multinationals and lowers the cost of US exports.

"There's no new bad news except for the hurricane barrelling down on Texas, so the path of least resistance is flat or higher" for stocks, said Art Hogan, chief market strategist at Wunderlich Securities.

The Dow Jones Industrial Average gained 0.1 per cent to 21,813.67.

The broad-based S&P 500 climbed 0.2 per cent to 2,443.05, while the tech-rich Nasdaq Composite Index added 0.1 per cent at 6,265.64.

Petroleum-linked stocks gained as some oil producers curtailed production due to Hurricane Harvey and gasoline prices rose in anticipation of refinery outages. Chevron and ConocoPhillips both gained 0.7 per cent, while Schlumberger rose 1.6 per cent.