The US-based rights group Human Rights Watch (HRW) reported on Sunday that Syrian government helicopters and planes had dropped the Russian-made cluster bombs along a main north-south highway that runs through the strategic town of Maarat al-Numan.

Rebels captured Maarat al-Numan from the Syrian government last week, severing the route between the capital, Damascus, and the country's commercial hub, Aleppo. Government forces have been trying to retake the strategic town since then.

HRW reported that the towns of Maarat al-Numan, Tamanea, Taftantaz and al-Tah had been targeted with cluster bombs. It said the bombs had also been used in the provinces of Aleppo, Damascus, Homs and Lattakia.

"Syria's disregard for its civilian population is all too evident in its air campaign, which now apparently includes dropping these deadly cluster bombs into populated areas," said Steve Goose, the arms director of HRW.

Banned under international law

Cluster bombs have been banned by 109 countries under an international treaty because they are considered too dangerous to civilians. Syria is not a signatory to that agreement.

The bombs are designed to disperse up to 650 submunitions, blanketing a large area. But between five and 40 percent of the bomblets fail to detonate and subsequently act as anti-personnel mines. HRW reports that 98 percent of cluster bomb victims are civilians, while some 27 percent are children who mistake the bomblets for toys.

Although the cluster bombs in question were manufactured in Russia, it was not clear who had sold them to the Assad regime, according to HRW.

Syria-Turkey tensions

Syria's brutal 19-month conflict has killed more than 30,000 people and has affected another 2.5 million, according to the United Nations. There are 348,000 registered Syrian refugees in neighboring countries. The civil war in Syria has increasingly begun to spill over the country's borders and risks pulling neighbors such as Turkey directly into the conflict.

Syria banned all Turkish civilian aircraft from flying over its territory late on Saturday. The move came after Turkey had forced a Syrian passenger plane to land earlier in the week. Ankara says it seized munitions from the Damascus-bound plane, which was travelling from Moscow. Russia has said the plane was carrying dual-use radar equipment.

Syria and NATO member Turkey also exchanged artillery fire across their common border multiple times last week, after a Syrian shell killed 5 Turkish nationals in the border town of Akcakale on October 3. The Turkish parliament subsequently approved cross-border military operations, should the government deem them necessary.

During talks with his Turkish counterpart, Ahmet Davutoglu, on Saturday, German Foreign Minister Guido Westerwelle said Berlin stands on the side of its ally Turkey, but also called on Ankara to exercise restraint.

UN-Arab League peace envoy Lakhdar Brahimi also held talks with Turkish leaders in Istanbul on Saturday. He is expected to travel to Syria's main regional ally, Iran, on Sunday and then to Iraq on Monday.

slk/tj (AFP, Reuters)