Hugo Chavez, the charismatic and controversial President of Venezuela, has died.
He had been seriously ill with cancer for more than a year, undergoing several operations in Cuba, and had not been seen in public for several months.
Vice-president Nicolas Maduro made the announcement on Tuesday evening, flanked by political and military leaders.
Earlier, Mr Maduro said Mr Chavez, 58, had a new, severe respiratory infection and had entered "his most difficult hours".
In an emotional address from a military hospital in Caracas, a tearful Mr Maduro said Hugo Chavez died at 4.25pm on Tuesday (local time) "after battling a tough illness for nearly two years".
Mr Chavez entered hospital on 18 February to continue chemotherapy after two months in Cuba, where he underwent another round of cancer surgery on 11 December last year - his fourth since June 2011.
Photos released in February showed him in his hospital bed in Havana with his two daughters at his side.
Venezuelans will now vote for a new president in 30 days. Foreign Minister Elias Jaua announced on Tuesday that Mr Maduro would act as interim president.
The announcement appears to contradict the constitution, which says that the National Assembly president takes over the presidency if the president dies.
The government has deployed the military to keep peace on the streets.
Hugo Chavez first came to prominence as the leader of a failed coup in 1992. Six years later, he was swept into office in a wave of popular support and won another term as president in October 2012.
A habit of impromptu policy-making was integral to his style from the start of his 14 years in power.
Time and again, Mr Chavez would make major decisions on an ad-hoc basis - often during the course of a rambling and unscripted weekly television broadcast to the nation, known as Alo Presidente, the BBC reports.
He was particularly prone to quick-fix solutions in economic policy, resorting to regular currency devaluations, expropriations of private firms and public-sector pay rises rather than tackling underlying structural problems in the economy.
This approach continued even as Mr Chavez lingered on his sickbed in Cuba, with a 32% devaluation of the bolivar in February.
As a result, Mr Chavez bequeaths a nation beset by crumbling infrastructure, unsustainable public spending and under-performing industry.
Supporters say Hugo Chavez spoke for the poor, but critics say he had become increasingly autocratic and wasted Venezuela's oil revenues.