TIKRIT, Iraq - The government declared victory in Tikrit on Wednesday over extremists of the Islamic State group, and it warned the militants holding other Iraqi provinces that they would be the next to fall.

Prime Minister Haider al-Abadi walked triumphantly along a street in Tikrit, carrying an Iraqi flag and surrounded by jubilant forces.

Across the border in Syria, however, Islamic State fighters made their deepest foray yet into the capital of Damascus by infiltrating a Palestinian refugee camp, according to opposition activists and Palestinian officials.

Iraq's victory over the extremists in Tikrit was seen as a key step toward eventually driving the militants out of Mosul, Iraq's second-largest city and the capital of Nineveh province.

Defense Minister Khalid al-Obeidi announced the victory, saying security forces have "accomplished their mission" in the month-long offensive to rid Saddam Hussein's hometown and the broader Salahuddin province of the militant group.

"We have the pleasure, with all our pride, to announce the good news of a magnificent victory," Obeidi said in a video statement, and he named the other Iraqi provinces still being held by the ISIS militants.

"Here we come to you, Anbar! Here we come to you, Nineveh, and we say it with full resolution, confidence, and persistence," he said.

Abadi said that military engineering units still need more time to clear Tikrit of booby traps and looked to the next steps for the city and province.

The extremists seized Tikrit last summer during its advance out of Syria and across northern and western Iraq.

Iraqi forces, including soldiers, police officers, Shiite militias and Sunni tribes, launched a large-scale operation to recapture Tikrit on March 2. Last week, the United States launched airstrikes on the embattled city at the request of the Iraqi government.

Recapturing Tikrit is seen as the biggest win so far for Baghdad's Shiite-led government. The city is about 80 miles north of Baghdad on the road connecting the capital to Mosul. Retaking it will help Iraqi forces have a major supply link for any future operation against Mosul.