A decree issued by the office of President Ilham Aliyev says, Azerbaijan has brought forward the date of a planned presidential election to April 11 from October 17.
Azerbaijan's strongman Ilham Aliyev on Monday called a snap presidential vote for April, six months ahead of schedule, as opposition politicians slammed the surprise move.
Aliyev, in power since succeeding his father Heydar Aliyev in 2003, has been nominated as the ruling party's candidate for the election for what would be his fourth term.
"Set the date of the election of the President of the Republic of Azerbaijan on April 11," Aliyev ordered in a decree posted on his website without providing an immediate explanation for the move.
The oil-rich country was initially set to hold the vote on October 17.
Last week, the deputy chair of the ruling Yeni Azerbaijan party, Ali Akhmedov, said that Aliyev planned to run for a fourth consecutive term.
"No-one knows what the true reason for calling a snap vote is," political anayst Hikmet Hadjizade said.
Reaction to early election
The decision sparked strong criticism from opposition parties.
"The Aliyevs have been in power for some 45 years already and that contradicts the principles of a democratic republic," the leader of the opposition Popular Front party, Ali Kerimli, said.
The veteran politician said the decision to hold early elections was aimed at shortening the campaign period and "hampering the opposition's efforts to prevent vote rigging".
So far, two opposition candidates - Musavat party leader Isa Gambar and the chairman of the Classical Popular Front Party Mirmahmud Miralioglu - have announced plans to run for president.
Aliyev was re-elected in 2008 and 2013 in polls that were denounced by opposition parties as rigged.
In 2009, Aliyev amended the country's constitution so he could run for an unlimited number of presidential terms, in a move criticised by rights advocates who say he could become a president for life.
In 2016, Azerbaijan adopted controversial constitutional amendments, extending the president's term in office to seven years from five.
The changes drew criticism from the Council of Europe constitutional law experts as "severely upsetting the balance of powers" and giving the president "unprecedented" authority.
Cementing his family's decades-long grip on power, the president last year appointed his wife Mehriban Aliyeva as first vice president.
Aliyev's "goal appears to be a political environment in which the Aliyev dynasty is unchallenged," a US diplomatic cable carried by whistleblowing organisation Wikileaks said in 2009.
"Clinging on to power"
Supporters have praised the Aliyevs for turning a republic once thought of as Soviet backwater into a flourishing energy supplier to Europe.
But critics argue they have crushed the opposition and used their power to amass a fortune that funds a lavish lifestyle for the president and his family.
"Ilham Aliyev is clinging on to power to continue appropriating the country's riches," Khadija Ismayilova, an award-winning journalist and anti-corruption crusader, said.
"Practically all of Azerbaijan's natural and economic resources are under the Aliyev family's control," said the journalist who had spent 17 months in jail in 2014-2016.
In 2010, The Washington Post wrote about lavish property worth $75 million (60 million euros) in Dubai in the names of the president's son Heydar - who was a schoolboy at the time - and his daughters Arzu and Leyla.
Aliyev has denied accusations of rights abuses and corruption.
Azerbaijan is locked in a bitter dispute with Armenia over separatist Nagorny Karabakh region, which has been under Armenian control since it was seized during a bloody conflict in the early 1990s after the break-up of the Soviet Union.
Energy-rich Azerbaijan, whose military spending exceeds Armenia's entire state budget, has repeatedly threatened to take back the breakaway region by force.