Wall Street moved lower overnight as Greek lawmakers prepared to vote on a proposal that would secure the cash-strapped country its third international bailout.
In Athens, riot police and Greek anti-austerity protesters clashed in front of the nation's parliament. Lawmakers are due to vote soon on reforms needed to secure the new bailout plan.
In late afternoon trading in New York, the Dow Jones Industrial Average slipped 0.11 per cent, the Standard & Poor's 500 Index fell 0.22 per cent, while the Nasdaq Composite Index shed 0.24 per cent.
"If you take how far we've come in the last three days, throw a riot on TV and toss in the fact that it appears that Greek parliament is still debating this package - that's enough to hit the market late in the afternoon on a quiet day," Michael Antonelli, an institutional equity sales trader and managing director at Robert W Baird & Co in Milwaukee, told Bloomberg.
US Federal Reserve Chair Janet Yellen told the House Financial Services Committee in Washington she expects policy makers to raise rates this year as economic growth improves.