Timeline: Venezuela's leadership battle

The military has generally supported Mr Maduro (L) in the stand-off with Mr Guaidó

Venezuelan opposition leader Juan Guaidó has vowed to end President Nicolás Maduro's rule amid an ongoing power struggle between the two men.

Mr Guaidó, who declared himself "acting president" on 23 January in a move recognised by several countries, claims that Mr Maduro is a "usurper" because he was re-elected in polls that have been widely disputed.

So how did we get here?

• Who is parliament leader Juan Guaidó?

• Maduro: Dictator or defender of socialism?

• How the political situation escalated

A timeline of key events in the unfolding saga:

4 April (2013): Nicolás Maduro is narrowly elected president of Venezuela after the death of long-serving socialist leader Hugo Chavez. The vote is marred by claims of fraud by the opposition.

18 February (2014): A wave of protests against Mr Maduro leads to the arrest of opposition leader Leopoldo Lopez, who remains under house arrest.

29 March (2017): Venezuela's Supreme Court says it is taking control of the National Assembly, prompting months of anti-government protests that leave 100 dead. The Supreme Court reverses its decision.

17 July: More than seven million Venezuelans vote in an opposition-organised referendum against Mr Maduro's plans to create a new body with the power to control the National Assembly.

20 May (2018): Mr Maduro wins snap election. The two leading opposition candidates reject the results, saying the election was marred by vote-rigging.

8 November: The UN announces that the number of refugees and migrants who have left Venezuela has passed three million. Venezuela's economy is tanking, creating widespread food and medicine shortages.

10 January (2019): Mr Maduro is inaugurated as president. The little-known new leader of the National Assembly, Juan Guaidó, calls the president a "usurper".

21 January: As Venezuela's economy continues to fail, a Caracas-based charity says it has recorded at least 107 episodes of looting and several deaths across the country.

23 January: Citing emergency powers, Mr Guaidó declares Mr Maduro's leadership illegitimate and claims the presidency. He is recognised by the US and several Latin American countries, creating two rival claims to the office.

21 March: A top aide to Mr Guaidó is arrested and charged with terrorism. Roberto Marrero, 49, is accused of planning "acts of sabotage".

30 April: Venezuelan authorities say they are tackling a small coup attempt after Mr Guaidó appears in a video surrounded by men in uniform talking about the "final phase" of ending Mr Maduro's rule.