Romania detained six people on charges of trying to overthrow the state with Russia’s help, prosecutors said on Thursday, and a 101-year-old former army major general said his home had been raided as part of the investigation.

Romanian police say six people have been detained for allegedly organizing a criminal group that colluded with Russia to plot a coup against the government.

Romanian prosecutors said on Thursday they had detained six people on charges of trying to overthrow the state with the help of Russia, marking a dramatic escalation of tensions between Bucharest and Moscow.

Romanian prosecutors detained six people suspected of allegedly plotting to overthrow the government and withdraw the Black Sea nation from NATO with Russia’s help.

The case involving allegations of Russian backing for a plot to overthrow the government comes at a critical time for Romania. The Constitutional Court has annulled the results of presidential elections in October due to irregularities, including apparent meddling by Russia. New elections are scheduled for May.