U.S. stock index futures were a touch lower on Monday, indicating a flat to slightly weak start to the week for Wall Street amid nervousness about volatile bond markets and nagging concern about Greece's future.
Bond markets were firmly in focus following last week's sharp sell-off. Benchmark 10-year Treasury yields soared to their highest level in eight months on Friday, as prices tumbled, after data showed the U.S. economy created 280,000 jobs in May, beating analyst expectations for a rise of 225,000.
"Equity markets are set for another volatile week after facing much drama last week on every end," Naeem Aslam, chief market analyst, at AvaTrade said in a note. "Greece and the U.S. economic health with respect to a hike in interest rate will dictate most of the trading action this week."
Stock market futures for the Dow Jones Industrial Average, Nasdaq and S&P 500 all traded one to 6.5 points lower in European trade, suggesting a flat to slightly negative open for U.S. equity markets.
U.S. stocks closed narrowly mixed on Friday as investors weighed up developments in Greece and a spike in bond yields following the closely watched non-farm payrolls report.
Analysts said strength in U.S. jobs data could encourage the Federal Reserve to raise interest rates sooner rather than later, with this week's economic numbers likely to come under scrutiny for further clues on the timing of a possible rate hike.
Thursday's May retail sales data is expected to be this week's most important data release.
In the meantime, developments outside the U.S. were expected to stay in focus.
The European Commission's President Jean-Claude Juncker on Sunday warned Greece was running out of time to secure a cash-for-reforms deal with its creditors and prevent a debt default.
Turkey was also in the spotlight after the country's President Tayyip Erdogan suffered a setback in his plan to boost the powers of the presidency on Sunday after the ruling AK Party failed to win an outright majority in a parliamentary election for the first time.
Turkish stocks tumbled 8 percent in early Monday trade, while the Turkish lira slid to a record low of 2.8 to the U.S. dollar.
Asian shares meanwhile extended their losses on Monday as data showing Chinese imports tumbled 17.6 percent in May from a year earlier fuelled concerns about a slowdown in China's economy – the world's second largest.
Europe's major stocks all traded in negative territory, with Germany's Dax index down 0.6 percent.
Elsewhere, the Group of Seven leaders meeting in Germany on Sunday said they would keep sanctions against Russia in place until President Vladimir Putin and Moscow-backed separatists fully implement the terms of a peace deal for Ukraine.