After the chief of the mercenary group Wagner, Yevgeny Prigozhin said his forces had crossed the border from Ukraine, the Russian authorities have tightened and strengthened security measures in several regions amid Prigozhins open threat.Wagner chief, Prigozhin has vowed to “go to the end” topple the leadership of the Russian military, whom he accused of launching strikes on his men, while the countrys prosecutor general said he was under investigation for armed rebellion.Military and security tightened in several regions amid Wagner chiefs threatAccording to the governor of the Lipetsk region of Moscow, Igor Artamonov said, “A decision has been taken to reinforce security measures in the region.”The governor also urged the locals to remain calm, saying, “I ask everyone to remain calm.” The region of Lipestsk is approx. 400 km (250 miles) south of Russias capital city, Moscow.Moreover, in the southern region of Rostov, the authorities have asked the residents to stay home.Officials urged residents to remain calm and stay homeTaking notes from the prevailing situation, Rostov governor Vasily Golubev said on social media, Law enforcement agencies are doing everything necessary to ensure the safety of residents. He added, “I asked everyone to stay calm and stay home.”Earlier, Moscow authorities instituted tighter security measures, and local media published amateur footage showing armoured vehicles deploying throughout the capital, including near the defense ministry, according to the media reports. Biggest threat to Putins authorities since its invasion of UkraineAhead of receiving one of the biggest threats by Wagner chief, President Vladimir Putin himself is close-watching the updates from the security officials on their efforts to counter the “attempt at an armed mutiny” by Yevgeny Prigozhin, said Kremlin spokesperson Dmitry Peskov,The threat has also marked the most dramatic escalation in a long-running feud between the mercenary leader and Russias military establishment, resulting in the spiraled and biggest challenge to Russian President, Putins authority since he sent troops into Ukraine almost 16 months ago.