Nationalist protesters force their way into parliament last week, attacking opposition MPs. Among the injured was Zoran Zaev, who hopes to be prime minister

The tiny Balkan republic of Macedonia risks becoming a new battleground between Russia and the West after a week of violence during which a mob including pro-Moscow nationalists stormed parliament, injuring dozens of MPs.

Serbia and other neighbouring countries deployed troops amid fears that the violence would spill over their borders as Nato, EU and US officials condemned the assault and pleaded for calm.

Western policy makers are concerned that a potential escalation in Macedonia could reignite ethnic tensions that have been simmering in the region since the bloody ethnic wars of the 1990s that were ended by an American-led military intervention.

European officials have also expressed “serious concerns” about Russian involvement in the crisis, after the Kremlin sided with the nationalists of the centre-right