NEW YORK (AFP) - Wall Street stocks finished lower on Friday (April 28) as nervousness about North Korea and other geopolitical hotspots offset positive momentum from a batch of mostly strong corporate earnings.

Art Hogan, chief market strategist at Wunderlich Securities, said investors were reluctant to commit additional funds ahead of the weekend, much like last week, when skittishness ahead of the French presidential election depressed equities.

"It's very typical of the last three or four weeks. Friday afternoon seems to be the unwind day," he said. "By that, I mean no one wants to take a big bet when you're heading into the weekend."

The Dow Jones Industrial Average dropped 0.2 per cent to end the week at 20,940.51.

The broad-based S&P 500 shed 0.2 per cent to close at 2,384.20, while the tech-rich Nasdaq Composite Index lost a hair to finish at 6,047.61, retreating from a record.

Google parent Alphabet jumped 3.6 per cent after reporting a 29 per cent jump in quarterly profit to US$5.4 billion (S$7.5 billion). Ad revenues rose and did not appear to show any effects from an ad boycott of YouTube earlier this year after revelations that ads were placed alongside videos showing hateful content.

Intel dropped 3.4 per cent despite reporting first-quarter net income rose 44 percent to US$3 billion, as analysts were disappointed in the growth in some businesses, such as its data centre group.

Oil giants ExxonMobil and Chevron rose 0.5 per cent and 1.2 per cent, respectively, after the companies reported sharply improved quarterly results due to higher oil prices.

Among others reporting earnings, companies experiencing large share moves were Expedia, down 1.8 per cent, Starbucks, down 2 per cent, and Western Digital, up 3.9 per cent.