An international human rights group says Syrian government forces and the Russian military have been carrying out daily cluster bomb attacks over the past few weeks. The Human Rights Watch (HRW) report, released Monday, says that internationally banned cluster munitions were used in at least 14 attacks across five provinces since Jan. 26. HRW says the attacks killed at least 37 civilians, including six women and nine children, and wounded dozens. HRW says the International Syria Support Group (ISSG) that will meet in Germany on Thursday "should make protecting civilians and ending indiscriminate attacks, including with cluster munitions, a key priority." The ISSG includes 17 regional and world powers trying to end Syria's conflict, which has killed more than 250,000 people since March 2011. The United Nations said that hundreds of thousands of civilians could be cut off from food supplies if Syrian government forces encircle rebel-held parts of Aleppo. Syrian government forces, backed by Russian air strikes and Iranian and Lebanese Hezbollah fighters, have launched a major offensive in the countryside around Aleppo, which has been divided between government and rebel control for years. The assault to surround Aleppo, once Syria's biggest city with 2 million people, amounts to one of the most important shifts of momentum in the five year civil war that has killed 250,000 people and already driven 11 million from their homes. The United Nations is worried the government advance could cut off the last link for civilians in rebel-held parts of Aleppo with the main Turkish border crossing, which has long served as the lifeline for insurgent-controlled territory. "It would leave up to 300,000 people, still residing in the city, cut off from humanitarian aid unless cross-line access could be negotiated," the United Nations Office for Coordination of Humanitarian Affairs said in an urgent bulletin. If government advances around the city continue, it said, "local councils in the city estimate that some 100,000-150,000 civilians may flee." German Chancellor Angela Merkel accused Russia this week of bombing civilians, against a UN Security Council resolution Moscow signed up to in December.