Syrian President Bashar al-Assad won a new seven-year term with nearly 90% of a vote in a poll branded "illegitimate" by the opposition and a "non-election" by Washington.
Assad said Thursday that "the high turnout was a strong message to the West and the countries implicated in the war on Syria."
Official figures put turnout for Tuesday's election, which was contested only in government-held areas, at more than 73%.
"The Syrian people... is determined to choose their fate on their own and looks to the future," the re-elected leader said in a meeting with an Iranian parliamentary delegation.
Tens of thousands took to the streets in government-held areas of Syria even before the results were announced Wednesday evening, waving portraits of Assad and the official Syrian flag.
As celebratory gunfire erupted in the capital and loyalist areas across Syria, at least 10 people were killed as the bullets fell back to earth, said the Syrian Observatory for Human Rights.
In the roughly 60% of the country controlled by rebels, activists reacted with the Arab Spring slogan that has been the rallying cry of their uprising — "The people want the fall of the regime."
Pro-government newspapers all carried front-page photographs of the re-elected president. Images of Assad in suit and tie, or military uniform, filled the programming of state television.
A source close to the regime said Assad would be sworn in for a third term on July 17, addressing parliament and laying out his new policies.
The main opposition National Coalition called the vote illegitimate and pledged that "the people are continuing in their revolution until its goals of freedom, justice and democracy are reached."
Rebels are massively outgunned by Syria's army, which is backed by Russia, Iran and Lebanon's powerful Shiite movement Hezbollah, and the opposition frequently calls on states that back the revolt to better arm the rebellion.
Pro-regime daily Al-Watan said the election was "just as important as that being fought by our brave soldiers on the frontlines" against the three-year rebellion against Assad.
'Great big zero'
British foreign secretary William Hague described the election as an insult.
"Assad lacked legitimacy before this election, and he lacks it afterwards," he said. "This election bore no relation to genuine democracy."
US secretary of state John Kerry called the poll a "great big zero".
"With respect to the elections that took place, the so-called elections, the elections are non-elections," he said in neighbouring Lebanon on Wednesday.
"Nothing has changed" as a result, Kerry said, and urged Assad's foreign backers to take action to bring an end to the conflict that has killed more than 162,000 people and driven millions from their homes.
But Russia insisted Syrians had chosen their country's future by voting in "legitimate" polls.
"It's unacceptable to ignore the opinion of millions of Syrians who... came to polling stations and made a choice in the interests of the future of the country," foreign ministry spokesman Alexander Lukashevich said.
"In Moscow the vote is seen as an important event that ensures the continued function of state institutions in Syria according to the constitution of this sovereign country," he said.
"We have no basis to cast doubt on the legitimacy of these elections.
"At least Russian observers came to the conclusion that they took place in a transparent atmosphere, despite all the complex security conditions in this country, and they noted a very high turnout," added Lukashevich.
Russia felt "disappointment" at the "shallow politicised reaction" to the polls from "certain international partners," he said.
And North Korean leader Kim Jong-Un congratulated Assad, saying his election "marked an important occasion in the struggle of the Syrian people to meet all challenges of the imperialists and hostile forces and protect the sovereignty and security of the country."