Wall Street moved lower overnight with European equities, while US Treasuries rose, amid concern about the hardening of stances in talks between Greece and its international creditors as this month's deadline looms large.
Talks between Greece and its creditors broke down on Sunday. This Thursday euro-zone finance ministers are set to meet with Greece's debt firmly on the agenda.
"It doesn't need to happen this week, the deadlines are very fluid," Witold Bahrke, an asset-allocation strategist at Nomura International in London, told Bloomberg News. "But if we're in July and we don't have a deal, I would expect some nasty volatility around European assets and I think this will also affect central banks."
US Federal Reserve policy makers start their two-day meeting on Tuesday, with Chair Janet Yellen scheduled to hold a press conference on Wednesday.
In late trading in New York, the Dow Jones Industrial Average fell 0.49 percent, the Standard & Poor's 500 Index slid 0.38 percent, as did the Nasdaq Composite Index.
Yields on 10-year bonds traded three basis points lower at 2.36 percent, after falling as low as 2.31 percent earlier in the day.