Russia's permanent representative to Nato has said that Moscow would react "negatively" to any increased Nato military presence in eastern Europe.
In an interview published on the Russian mission's website, Ambassador Alexander Grushko said:
We have already expressed many times our concern about recent increased activity along the Russian borders, on the ground, in the air and in the sea. This [increased Nato military presence] worries us for many reasons. First of all, there is no ground for increased NATO activities.
He warned that any move by Nato to "begin military preparations" could "seriously weaken regional and global security".
Angus Raffle, 8, says his surprise meeting with the President at Stonehenge was "awesome". His mother says she "squealed like a teenager".
The language has been ramped up at this Nato summit, yet caution appears the order of the day after the mistakes of recent history.
The US President's motorcade pulled up at the school with his black stretch limousine bearing a Welsh flag for the first time in history.