MOSCOW (Reuters) - Vladimir Putin was named acting president on Dec. 31, 1999, by then-president Boris Yeltsin. He has been in office as president or prime minister ever since, a period spanning two decades.

Russian President Vladimir Putin listens to Minister of Civil Defence, Emergencies and Disaster Relief Yevgeny Zinichev during a meeting in Moscow, Russia December 27, 2019. Sputnik/Aleksey Nikolskyi/Kremlin via REUTERS

Here are some highlights of Putin’s 20 years in power:

Aug. 9, 1999 - During an economic crisis, President Yeltsin names little-known security chief Vladimir Putin as his fifth acting prime minister in less than a year, and says he wants Putin to succeed him as president. In the following weeks, bombings of apartment blocks across Russia kill more than 300 people, in attacks Putin blames on Chechen militants. His popularity is boosted by his tough response, which includes the aerial bombing of parts of Chechnya and an assault to recapture the breakaway southern province. Some Kremlin critics question if Chechen militants were really behind the apartment bombings.

Dec. 31, 1999 - An ailing Yeltsin resigns and names Putin acting president.

March 26, 2000 - Putin wins his first presidential election.

Aug. 12, 2000 - The Kursk nuclear-powered submarine sinks to the bottom of the Barents Sea, killing all 118 crew after an explosion onboard. Putin’s image suffers a jolt after he comments on the crisis only after four days.

2002 - Chechen militants take more than 800 people hostage at a Moscow theater. Special forces end the siege, but use a poison gas in the process which kills many of the hostages.

2003 - Oil tycoon Mikhail Khodorkovsky is arrested and charged with fraud. He is later found guilty and jailed in a case his supporters say was punishment for his meddling in politics. He is only released in 2013 after Putin pardons him.

March 2004 - Putin wins second term as president with more than 70 percent of the vote after oil prices fuel a consumer boom and raise living standards, a trend that continues for another four years.

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September 2004 - Islamist fighters seize more than 1,000 people in a school in Beslan, southern Russia, triggering a three-day siege that ends in gunfire. A total of 334 hostages are killed, more than half of them children. Some parents say the authorities botched the handling of the siege and blame Putin.

December 2004 - Putin scraps direct elections for regional governors, effectively making them Kremlin appointees. Putin says the move is needed to keep Russia united.

2005 - Putin describes the 1991 collapse of the Soviet Union as the “greatest geopolitical catastrophe” of the 20th century.

2006 - Investigative journalist Anna Politkovskaya, a critic of rights abuses in Chechnya, is murdered in Moscow on Putin’s birthday. Kremlin critic Alexander Litvinenko dies in London that same year after being poisoned with a radioactive substance. A British inquiry years later concludes he was killed by Russian agents.

2007 - Putin gives a speech in Munich in which he lashes out at the United States, accusing Washington of the “almost uncontained hyper use of force in international relations”.

May 2008 - Constitutional limits on him serving more than two consecutive presidential terms see Putin become prime minister after his ally, Dmitry Medvedev, becomes president.

August 2008 - Russia fights and wins a short war with Georgia. Tbilisi loses control over two breakaway regions that are garrisoned with Russian troops.

2012 - Putin returns to the presidency, winning re-election with over 60% of the vote after a decision to extend presidential terms to six from four years. Large anti-Putin protests take place before and after the vote, with critics alleging voter fraud.

Feb. 7-23, 2014 - Russia hosts the winter Olympic games in the Black Sea resort of Sochi.

Feb. 27, 2014 - Russian forces start annexing Ukraine’s Crimea region after Ukrainian protesters oust their country’s Russia-friendly president Viktor Yanukovich. Russia incorporates Crimea the following month after a referendum condemned by the West. The United States and EU go on to impose sanctions on Moscow.

April 2014 - A pro-Russian separatist revolt breaks out in eastern Ukraine which results in a conflict, still ongoing, which hands the rebels control of a vast swath of territory and leaves more than 13,000 people dead. Western nations accuse Russia of backing the revolt; Moscow denies direct involvement.

Sept. 30, 2015 - Russia launches air strikes in Syria in its biggest Middle East intervention in decades, turning the tide of the conflict in President Bashar al-Assad’s favor.

November 2016 - Donald Trump is elected president of the United States after promising to improve battered ties with Moscow. However, U.S. authorities determine Russia tried to interfere in the election in Trump’s favor, casting a pall over U.S-Russia ties despite Moscow’s denials.

March 4, 2018 - A former Russian spy, Sergei Skripal, and his daughter are poisoned in England with a nerve agent. They survive but a woman who lives nearby dies after her partner brings home the poison found in a discarded perfume bottle. Britain accuses Russia, which denies involvement.

March 19, 2018 - Putin wins a landslide re-election victory and a mandate to stay in office until 2024.

June/July 2018 - Russia hosts the men’s soccer FIFA World Cup.

July 2019 - Protests break out in Moscow over a municipal election which the anti-Kremlin opposition says is unfair. Those protests grow into Moscow’s biggest sustained protest movement in years before fizzling out.

December 2019 - Putin boasts of his country’s lead in hypersonic weapons and says other countries are trying to catch up.