Forces loyal to Syrian dictator Bashar al-Assad are struggling to seize the last remaining rebel stronghold in northwestern Syria held by Turkey-backed opposition fighters and al-Qaeda-linked jihadis who have joined forces against the regime, Reuters reported Wednesday.

“I expect the battles to continue for a time because it has become a bone-breaking battle,” Col. Mustafa Bakour, a commander in the Jaish al-Izza rebel group, told Reuters, noting that coordination among the opposition forces, including the jihadis, is a significant factor in thwarting the attacks by the Assad forces.

With the help of Iran and Russia, Assad has been able to re-conquer most of Syria except swathes of the territory in the north, held by U.S.-backed Kurdish forces and to a much lesser extent al-Qaeda-linked jihadis and Turkish-backed rebels.

The al-Qaeda-linked terrorists in Syria capitalized on the near single-minded focus of the international efforts against their rival the Islamic State (ISIS/ISIL) and they now control more territory than any other terrorist group in and around Idlib province where they have established an Islamic emirate.

On Wednesday, Reuters reported:

President Bashar al-Assad’s assault in the northwest has been met with a painful rebel counterpunch that underlines Turkish resolve to keep the area out of his hands and shows why he will struggle to take back more of Syria by force. More than two months of Russian-backed operations in and around Idlib province have yielded little or nothing for Assad’s side. It marks a rare case of a military campaign that has not gone his way since Russia intervened in 2015. … The Idlib area is dominated by Tahrir al-Sham, the [al-Qaeda-linked] jihadists formerly known as the Nusra Front. Proscribed as a terrorist group by the U.N. Security Council, the group has set aside past conflict with Turkish-backed rebels to defend the northwest.

Citing an unnamed rebel source, Reuters noted that Turkey is arming the opposition fighters collaborating with the al-Qaeda-linked jihadis in northern Syria with “guided anti-tank missiles.”

“They’re even targeting personnel with these missiles … it means they are comfortably supplied,” the source told Reuters on condition of anonymity because he was discussing opposition capabilities.

Reuters acknowledged the Turkish government did not answer requests for comment on allegations that Ankara is providing weapons to opposition troops in Syria.

In 2016, the Nusra Front changed its name to Jabhat Fateh al-Sham (JFS) after claiming to have broken ties with al-Qaeda, an allegation that various analysts, the United Nations, and the U.S. government have dismissed.

JFS is now spearheading the Hayat Tahrir al-Sham (HTS) jihadi coalition in Syria, which the U.S. considers the latest iteration of al-Qaeda in the country.

In September 2018, pro-Syrian opposition Turkey and Assad’s ally Russia reached a failed agreement to establish a buffer zone northern Syria’s Idlib province free of jihadis and their heavy weapons. Both countries have blamed one another for the failure.

In April, Assad regime forces, backed by Russian airstrikes, began its offensive to try to take back northwestern Syria from the rebels and the jihadis to no avail.

After a hiatus of more than two years, the U.S. military launched deadly airstrikes against the al-Qaeda-linked militants in Syria’s Aleppo province, which borders Idlib.

“This operation targeted AQ-S [al-Qaeda in Syria] operatives responsible for plotting external attacks threatening US citizens, our partners, and innocent civilians,” the U.S. military said after the strikes.

On Wednesday, the London-based Asharq Al-Awsat reported the recent negotiations between the United States and Russia have yielded “silent agreements,” allowing the American military to carry out airstrikes against al-Qaeda-affiliates in northwestern Syria and Moscow to take “calm steps” to contain Iran’s presence in the war-devastated country.

Reuters pointed out that it is unclear if Assad and his Russian and Iranian allies are on the same page when it comes to northwestern Syria, noting that Ankara has deployed forces there in agreement with Tehran and Moscow.

“Moscow has appeared keen to preserve its ties with Ankara even as its air force bombs in support of Assad: Turkey says Russia has intervened to stop attacks on Turkish forces from Syrian government-held territory,” Reuters reports.

The news outlet also highlighted the absence of Iranian-backed Shiite forces in the fight to seize territory in northwestern Syria.

Citing the U.K.-based Syrian Observatory for Human Rights, a group that monitors the conflict using ground sources, Reuters pointed out that hundreds of civilians and fighters have perished in the battle for northwestern Syria.

Rami Abdulrahman, the Observatory’s chief, described the operation as “a failure on all levels” for Russia and Assad.

Pro-government forces cannot win the battle for Idlib unless Moscow helps them on the ground, he said.

Reuters acknowledged that the U.S.-backed Kurds are also standing in the way of further advances by the Assad regime.