Syrian President Bashar al-Assad, who was sworn in for a new term on Wednesday, said Western and Arab states that have supported "terrorism" will pay a "high price" and that he would fight insurgents until security was restored to the whole country.
"Soon we will see that the Arab, regional and Western states that supported terrorism will pay a high price," he told his supporters at the presidential palace.
Assad also thanked Syria's allies for their support during the war, including Lebanon's Hezbollah.
"Let's not forget the faithful ones, the sons of the Lebanese resistance, those heroes who stood by our army heroes and gave martyrs to defend the resistance axis," Assad said, in a reference to Hezbollah.
Assad was sworn in for a new seven-year term on live TV, after his victory in an election that affirmed his grip on power more than three years into Syria's rebellion.
The vote was held in June in areas of central and northern Syria that remain under state control.
Assad dismissed criticism of the election, pointing to the participation of the other candidates in the elections, a first for Syria.
"The Syrian people can give lessons in democracy," he said.
He also hailed the Syrian people's steadfastness in the face of what he described as a conspiracy against the country.
"They wanted a revolution, but you have been the real revolutionaries. I congratulate you for your revolution and for your victory," Assad said. "Those who lost their way can now see clearly ... the monstrous faces have been unveiled, the mask of freedom and the revolution has fallen."
While saying that many people had fled from the terrorism of armed groups, Assad said he was optimistic that they would be able to return.
Assad has shored up his control over a strategic corridor of territory stretching north from Damascus, taking back major cities including Homs. Backed by Lebanese Hezbollah fighters, his forces are now squeezing rebels in Aleppo.
But to the east and northeast, large parts of the country are in insurgents' hands. The militant Islamic State has expanded its control in recent weeks, defeating other Islamist factions with new weaponry brought in from Iraq.
Official results showed Assad winning 88.7 percent of the vote. It was the first contested presidential election in Syria. Previous votes had been referendums to approve the appointment of Bashar and his father, Hafez al-Assad, who died in 2000.
Large areas of Syria have fallen to an insurgency dominated by terrorists, including a powerful al-Qaeda offshoot known as the Islamic State that has also seized swathes of Iraq.
Assad, supported by Russia and Iran, has defied calls by Western states for him to step aside during the conflict that started in 2011 with protests against his rule before descending into a war that has killed at least 170,000 people.