BEIRUT — U.S.-backed Syrian forces celebrated in the devastated streets of Raqqa on Tuesday after gaining control of the northern city that once was the heart of the Islamic State’s self-styled caliphate, dealing a major defeat to the extremist group that has seen its territory shrink ever smaller since summer.

Militants took over the vibrant metropolis on the Euphrates River in 2014, transforming it into the epicenter of their brutal rule, where opponents were beheaded and terror plots hatched.

It took thousands of bombs dropped by the U.S.-led coalition and more than four months of grueling house-to-house battles for the Syrian Democratic Forces to recapture Raqqa, marking a new chapter in the fight against the group whose once vast territory has been reduced to a handful of towns in Syria and Iraq.

“Liberating Raqqa is a triumph for humanity, especially women,” who suffered the most under IS, said Ilham Ahmed, a senior member of the SDF political wing.

“It is a salvation for the will to live an honorable life. It is a defeat to the forces of darkness,” said Ahmed, speaking to The Associated Press from Ein Issa, just north of Raqqa.