In this frame grab provided on Tuesday, Sept. 5, 2017, by Russian Defence Ministry press service, showing what they say is along-range Kalibr cruise missile launched by the Russian Navy Admiral Essen frigate in the Mediterranean Sea. The Russia's Defense Ministry say a Russian warship in the Mediterranean fired cruise missiles Tuesday toward Islamic State group targets in the eastern Syrian province of Deir el-Zour. (Russian Defence Ministry Press Service photo via AP)
In this frame grab provided on Tuesday, Sept. 5, 2017, by Russian Defence Ministry press service, showing what they say is along-range Kalibr cruise missile launched by the Russian Navy Admiral Essen frigate in the Mediterranean Sea. The Russia's Defense Ministry say a Russian warship in the Mediterranean fired cruise missiles Tuesday toward Islamic State group targets in the eastern Syrian province of Deir el-Zour. (Russian Defence Ministry Press Service photo via AP)

Beirut — Syrian troops and allied forces reached the eastern city of Deir el-Zour on Tuesday, breaching a three-year-old Islamic State siege on parts of the contested city near the Iraqi border, the army command and a war monitoring group said.

Lifting the siege on Deir el-Zour, parts of which have been ruled by the extremist group since January 2015, marks another victory for President Bashar Assad, whose forces have been advancing on several fronts against ISIS and other insurgents over the past year.

It also puts an end to a humanitarian crisis for the estimated 70,000 people who survived on erratic air drops of food and supplies during the 32-month siege. Syrian state media said dozens of trucks carrying aid are ready to move in.

The army command said in a statement that reaching Deir el-Zour marks “a strategic turn in the war against terrorism,” and that the city will be used as a “launching pad to expand military operations in the region.”

Syrian state TV said troops reached the western outskirts of the city and broke the siege after IS defenses collapsed.

Rami Abdurrahman, who heads the Britain-based Syrian Observatory for Human Rights, also reported that troops had breached the siege.

ISIS has suffered a series of major setbacks in recent months. Iraqi forces drove the extremists from the northern Iraqi city of Mosul in June, and U.S.-backed Syrian forces have seized more than half of the Syrian city of Raqqa, once the group’s self-styled capital.