U.S.-led coalition airstrikes against the Islamic group ISIS and other extremists in Syria have killed more than 860 people, including civilians, since they began in mid-September, a monitoring group said Wednesday.

The Britain-based Syrian Observatory for Human Rights said the vast majority of those killed — 746 people — were Islamic State militants, while another 68 were members of al-Qaeda's Syrian affiliate known as the Nusra Front. At least 50 civilians, including eight children and five women, also have been killed in the airstrikes, the group said.

In Baghdad on Wednesday, Prime Minister Haider al-Abadi shook up the country's military, relieving 26 army officers from their command, retiring 10 others and appointing 18 new commanders.

A statement posted on the official website of the prime minister's office said the changes were ordered "as part of efforts to reinforce the work of the military on the basis of professionalism and fighting graft in all its forms."

The statement did not elaborate, but a government official said the shake-up followed the findings of a probe ordered by al-Abadi last month on corruption in the military.

Under Iraq's constitution, al-Abadi, like Nouri al-Maliki before him, holds the post of General Commander of the Armed Forces. But it was al-Maliki, now a vice president, who had tightly controlled the military during his eight-year rule, with several elite units taking their orders directly from him.

Al-Abadi's move comes as Iraq's military and security forces, aided by the coalition's airstrikes, battle militants from the Islamic State group on multiple fronts to drive them out of about a third of the country they seized in a summer blitz. The army and security forces had melted away in the face of the onslaught but have since partially regrouped.

In northern Syria, meanwhile, Kurdish forces defending the town of Kobani from Islamic State militants took control of much of a strategic hill overlooking the town, local official Idriss Nassan and Kurdish fighter Dalil Boras said.

Nassan also said the Kurds managed to secure a road on the southeastern side of the town that the Islamic State had used to ferry supplies and reinforcements to its fighters besieging Kobani.

"This is big progress for the Kurdish forces," Nassan said.

The U.S.-led coalition's aerial campaign in Syria began before dawn on Sept. 23 in what President Barack Obama has called an effort to roll back and ultimately destroy the Islamic State group. The militant extremist group has been the primary target of the coalition's strikes, although on at least two occasions the United States has targeted what it says is a specific cell within the Nusra Front allegedly plotting attacks against American interests.

The airstrikes in Syria expanded upon a U.S.-led operation in neighbouring Iraq against ISIS group, which has seized control of a large chunk of territory spanning the two countries. Canada has six CF-18s fighters, two CP-140 Aurora surveillance aircraft and a CC-150 Polaris refuelling aircraft operating out of bases in Kuwait.

In Iraq, government security forces and Shiite militias have largely halted the militants' advance, even rolling them back from some areas with the help of coalition airstrikes. But heavy fighting still rages on multiple fronts, and attacks on government troops and civilians remain common, particularly in Baghdad.

The U.S. Central Command said the U.S. and allied nations conducted sixteen airstrikes in Syria and seven in Iraq since Monday. Most of those airstrikes were carried out near Kobani.