Censor.NET reports quoting Deputy Spokesperson for the State Department Mark Toner as saying at a Tuesday briefing.
"This was inexcusable and it frankly underscored the increasingly dangerous conditions under which these monitors are forced to operate," he said.
He stressed not only landmines pose danger to OSCE monitors in the Donbas. Other issues are access restrictions as well as threats and harassment.
"We are calling for an investigation into this. We want an investigation to take place. We believe that should be an OSCE-led investigation, because we want to find out exactly what happened," Toner said.
The spokesman added the U.S. would urge Russia to use its influence with the separatists to allow the OSCE to conduct a full and transparent and timely investigation into what happened.
As reported, a United States national was killed in OSCE SUV blast April 23 near the village of Pryshyb in the militants-held territory of Ukraine's eastern Luhansk region. Two more monitors, nationals of Germany and the Czech Republic, were injured.
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