British Greenpeace activist Anthony Perret, who was held in Russia following a protest over the country's Arctic drilling, said he was "chuffed" to be released.
Greenpeace's Arctic Sunrise Twitter feed states:
Anthony Perret, got out an hour ago, tells us "Chuffed to be out, it's quite nice really". #FreeTheArctic30
Great news: Kieron Bryan, the second Brit, has been released on bail in St Petersburg #FreeTheArctic30
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Michael Fallon has received reassurances from his US counterpart that security ties with Britain will "endure" following a vote for Brexit.
On Friday, police said it appeared the girl had shot herself in the face with the weapon.
The showers will be slow-moving, heavy and thundery at times, particularly in central and eastern areas.