Vladimir Putin, who is expected to win a fourth term in March 18 polls, has boosted Russia's profile as a power broker and military force but entangled it in intractable conflicts and hurt its economy with sanctions.
Russia backed long-term ally President Bashar al-Assad after he responded to Arab Spring protests in 2011 with a brutal crackdown, and Moscow has vetoed numerous UN resolutions condemning the Syrian regime.
It launched a bombing campaign in September 2015 that helped turn around the multi-front war. Multiple news reports have found evidence that Russian mercenaries are also fighting on the ground, which Moscow denies.
Russia is attempting to broker a peace settlement together with fellow regime-ally Iran and rebel-backer Turkey. The countries agreed to create de-escalation zones including in Eastern Ghouta where fighting escalated in February.
Last month Russia backed a UN resolution on a 30-day ceasefire and announced a daily "humanitarian pause" but violence continues to rage in Eastern Ghouta as the government forces mount an offensive. The conflict has claimed more than 340,000 lives.
Russia bitterly opposed pro-European movements in its neighbour Ukraine and responded to the toppling of Moscow-backed President Viktor Yanukovych in 2014 by annexing Crimea where Moscow already had its Black Sea fleet base.
Shortly afterwards a Russian-backed separatist movement took up arms in eastern Ukraine, sparking a conflict that has killed more than 10,000 people.
Russia's actions in Ukraine have prompted the European Union and the United States to impose sanctions on both companies and individuals, from business figures to politicians. In response, Moscow has imposed an embargo on key EU food imports.
Russia is also involved in frozen conflicts in other ex-Soviet countries, backing breakaway authorities in Transdniestr in Moldova and in Abkhazia and South Ossetia in Georgia, with whom it fought a brief war in 2008.
Putin initially appeared to welcome the election of Donald Trump before relations deteriorated into a new Cold War-style standoff, with the superpowers also deeply divided over the conflicts in Ukraine and Syria.
Washington has indicted 13 Russian citizens and threatened to issue sanctions over Russia's alleged meddling in the 2016 US presidential election, reportedly through a covert campaign organised on social media.
Trump has played down the allegations, however, while acknowledging Russia and other countries interfered in the race.
Russia has repeatedly voiced concern over Nato encroaching on its borders and opposes the anti-missile shield that the US and its Nato allies are deploying in eastern and central Europe.
Earlier this month, Putin unveiled a new arsenal of hypersonic weapons which are being developed and tested which he claimed could evade any air defence and anti-missile systems, prompting the US to accuse Moscow of breaching Cold War-era treaties.
Russia has retained some of its Soviet-era ties to the hardline isolationist regime in North Korea, with which it shares a land border, but backs United Nations resolutions condemning its multiple tests of nuclear weapons and missiles.
Moscow has repeatedly urged North Korea to return to six-party talks with Russia, the US, South Korea, Japan and China that broke down almost a decade ago.
Search for new allies
Dogged by Western sanctions, Russia has reached out to build new alliances, particularly with the powerful economies of China, where it has struck a deal to sell oil, and India, where state-controlled Rosneft has acquired a large stake in refiner Essar Oil.
It has also backed the socialist regimes of Hugo Chavez and his successor Nicolas Maduro in Venezuela. Along with China, Russia is the biggest lender to the crisis-stricken country.
Russia has affirmed "unshakeable solidarity" with Communist Cuba and last year criticized Trump for reversing Barack Obama's deal to restore ties with Havana.