BEIRUT: The Islamic State group has retaken large areas in the northern Syrian province of Raqqa that it recently lost to government troops, opposition activists said Tuesday.
Syrian troops have been on the offensive for nearly three weeks and had approached to within seven kilometers (four miles) of the Tabqa air base near Raqqa city, the de facto capital of the IS group's self-declared caliphate.
But the Britain-based Syrian Observatory for Human Rights said Tuesday that government forces lost all the territory they gained in Raqqa province since launching their offensive on June 2, adding that troops have been pushed back now to about 40 kilometers (25 miles) from Tabqa.
IS has been under pressure in Iraq, Syria and Libya in recent weeks, but the gains in Raqqa show it is still able to take on Syrian troops backed by Russian warplanes. The extremist group has used massive suicide bombings to break through its opponents' ranks.
The Syrian government has had no presence in Raqqa since August 2014, when IS captured the Tabqa air base and killed scores of captured government soldiers. The provincial capital, Raqqa, was the first city to fall to IS.
The IS-linked Aamaq news agency posted a video showing the extremists in control of Thawra oil field as warplanes strike nearby. Government forces had seized the field on Sunday only to lose it hours later.
Syrian journalist Eyad al-Hosain, who is embedded with the army, wrote on his Facebook page that even if special forces "retreat for hours they will come back." He added that after two days of fierce battles, the army had to withdraw from "some" of the positions it captured recently.
Al-Hosain added that the march toward Tabqa is ongoing but will take on "new dimensions," without elaborating.
The Observatory said 40 troops were killed over the past two days, raising to 93 the number of troops killed since the offensive began. It added that 126 IS militants have been killed in the area so far, including 21 since Sunday.
The Observatory said IS has brought reinforcements of some 300 fighters from the city of Raqqa.
Fighting between rebels and government forces meanwhile continued around the divided northern city of Aleppo and its outskirts, with opposition media outlets publishing videos purportedly showing the use of air-dropped incendiary cluster munitions on civilian areas in the northern Aleppo countryside. The munitions can cause excruciating and often fatal burns.
Opposition activists said the munitions were dropped by Russian jets, though this was not clear in the videos. A separate video, published by the Russian broadcaster Russia Today on YouTube Saturday, showed Russian jets in the Hemeimeem air base in Syria loaded with bombs labelled RBK-500 ZAB 2.5SM, a model of incendiary cluster munitions, according to the Geneva-based Landmine and Cluster Munition Monitoring group.
A 2013 report by Human Rights Watch said the Syrian air force was deploying the weapons in a "widespread" manner, often against civilians. Russia is a signatory to a 1980 convention prohibiting their use in civilian areas; the Syrian government is not.
In Geneva, Russia called for the resumption of peace talks that collapsed in April amid sharp disagreements between the government and the opposition.
"The only way to solve the Syria crisis and stop human rights violations in Syria is to resume the direct Syria talks as soon as possible with a wide participation of the opposition including the Syrian Kurds," said Aleksei Goltiaev, who heads the human rights team at the Russian mission in Geneva.
"Only the Syrian people, and not some influence from abroad, has the right to decide the future of their own country," Goltiaev said in a speech to the Human Rights Council.