US futures lower on Ukraine, Middle East turmoil

U.S. stock-index futures pointed to a lower open on Wall Street on Monday, with investor sentiment subdued due to ongoing geopolitical turmoil.

Allergan shares gained in early New York trading after the maker of medical devices and drugs said it would reduce its workforce by 13 percent.

The downing of the Malaysia Airlines Flight MH17 over near the Russia-Ukraine border remained in focus. Western leaders have set a Tuesday deadline for Russian President Vladimir Putin to allow full access to the crash site or face further sanctions. This follows "compelling" evidence that pro-Russian separatists and Russian military personnel shot down the plane by mistake with a Buk-M1 surface-to-air missile launcher.

The United Nations is also considering a resolution to demand that armed groups in Ukraine allow international investigators access to the crash site. A vote may come as early as Monday.

Sunday was one of the bloodiest days in the two-week Israeli offensive in Gaza. Despite heavy casualties, Israeli Prime Minister Benjamin Netanyahu warned that military operations could be expanded.

"With new U.S. sanctions on Russian firms, the downing of a airliner in Ukraine and greater fears of Middle East unrest, markets have been spooked with risk positions pared back," said Mizuho bank in a research note.

Just under 150 S&P 500 constituents, accounting for around one-third of the index market capitalization, will report second-quarter earnings this week. This includes a number of market heavyweights including Apple, Microsoft, Verizon and Coca Cola on Tuesday, followed by AT&T and Facebook on Wednesday and Amazon on Thursday.