NATO has expelled two Russian diplomats over a spy scandal, a move Moscow's ambassador to the military alliance said was intended to set back efforts by Russia and the United States to repair relations. Tensions between the former Cold War foes also rose on Thursday over pacts which Moscow said it signed with two rebel Georgian regions, giving it control over their borders. For a wrap of the news, please see [ID:nLU969829] The following are the key issues: u NATO's expulsion of two Russian diplomats – including the son of Russia's Brussels-based ambassador to the EU – deals a new blow to efforts aimed at mending ties that were frozen after Russia's war with Georgia last August. Analysts said the timing of the expulsion was unusual. It came on Wednesday, the same day that the alliance resumed formal talks with Russia at ambassadorial level. Russian President Dmitry Medvedev said the expulsions amounted to a challenge from the West and the Foreign Ministry said they were driven by elements inside the Western alliance that wanted to undermine ties with Moscow. Russia's ambassador to NATO, Dmitry Rogozin, said Moscow's response would be “harsh and decisive”. He did not elaborate, but previous spy rows between Russia and the West have often led to tit-for-tat diplomatic expulsions which run the risk of drawing both sides into an escalating cycle of retaliation. u The day after Moscow was informed of the planned expulsions, Russia took formal control over the de-facto borders of South Ossetia and Abkhazia, two Moscow-backed regions that broke away from Georgian rule in the 1990s. Russia views NATO with deep suspicion but Medvedev says he wants to mend ties with Washington after relations sank to post-Cold War lows under former US President George W. Bush. Analysts said the Kremlin may be seeking to test the nerves of NATO members now Barack Obama is in the White House. u NATO exercises in Georgia next week, another source of tension with Russia, were planned long ago, though Moscow voiced sharp criticism when the war games were formally announced.