NEW YORK, Aug. 24 (Xinhua) -- U.S. stocks eked out modest gains on Tuesday as the tech-heavy Nasdaq notched fresh record to finish above the 15,000 milestone for the first time.

A pedestrian walks past the New York Stock Exchange in New York on Oct. 30, 2020. (Photo: Xinhua)

The Dow Jones Industrial Average increased 30.55 points, or 0.09 percent, to 35,366.26. The S&P 500 was up 6.70 points, or 0.15 percent, to 4,486.23. The Nasdaq Composite Index rose 77.15 points, or 0.52 percent, to 15,019.80.

Six of the 11 primary S&P 500 sectors ended in green, with energy up 1.61 percent, leading the gainers. Consumer staples slipped 0.76 percent, the worst-performing group.

U.S.-listed Chinese companies traded mostly higher with nine of the top 10 stocks by weight in the S&P U.S. Listed China 50 index ending the day on an upbeat note.

Investors are awaiting a key event of the U.S. Federal Reserve as its annual Jackson Hole economic policy symposium will be held later this week.

The conference will be closely watched by market participants as Fed Chairman Jerome Powell could use the occasion to signal that the Fed is on track to tapering its asset purchase program later this year.

The market also cheered the news that the U.S. Food and Drug Administration on Monday granted full approval to the Pfizer/BioNTech COVID-19 vaccine for people age 16 and older.

"The main underlying themes that continue to support the market are strong earnings, a robust outlook, an economy that continues to rebound, and a growing jobs market," Kevin Matras, executive vice president at Zacks Investment Research, said Tuesday in a note, adding "the increase in virus cases remains a concern."

The average daily increase of cases in the United States was over 141,000 in the seven-day period ending Monday, compared with a seven-day average of around 52,800 daily cases a month ago, according to the latest data compiled by the U.S. Centers for Disease Control and Prevention.