Representatives of NATO countries are meeting in Brussels after member nation Poland said a Russian-made missile dropped on its territory near the Ukrainian border, resulting in two deaths on Tuesday.
NATO leaders have so far been careful not to lay blame, with alliance chief Jens Stoltenberg stressing that all facts must be established.
Poland's foreign minister has summoned the Russian ambassador, demanding an "immediate and detailed explanation."
Our reporter Rosie Birchard is in Brussels, where NATO is headquartered.
Out: attacks against Ukraine
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