A/HRC/21/32 Anti-Government armed groups also attacked Government forces, installations and checkpoints. 22. In late May 2012, conditions deteriorated, as seen in the an increase in the number of attacks by Government forces on population centres, using heavy weapons, including tanks and artillery shelling, helicopter rockets, cannons and mechanized infantry, as part of a campaign to clear anti-Government armed groups. Heavy weapons were used particularly in Dar’a, Homs, Hama, Idlib and Rif Dimashq, and expanded to the larger urban areas of Deir el-Zour, Damascus and Aleppo. These attacks were accompanied by an increase in planned and coordinated attacks by anti-Government armed groups targeting Government forces, as well as Government and civilian infrastructure, using small arms, improvised explosive devices and rocket-propelled grenades. 23. Allegations were made of the indiscriminate and disproportionate use of force by Government forces during armed clashes that took place in populated areas. Such use of force resulted in heavy civilian casualties and mass displacement of civilians inside and outside the country. While the United Nations is unable to verify the number of casualties, the Government reported that more than 7,000 citizens had been killed. Some Syrian nongovernmental organizations and opposition groups reported that between 13,000 and 17,000 citizens had been killed as a result of the crisis. 24. The Government did not provide any information on the withdrawal of heavy weapons from population centres during the reporting period, only stating that, when it had withdrawn heavy weapons from such areas during the visit of the League of Arab States observer mission, which was deployed in December 2011, the “terrorist armed groups” had reinforced their position quickly and continued to terrorize and intimidate civilians. 25. In its note verbale dated 16 July 2012, the Government of the Syrian Arab Republic reported that it had issued strict orders to security forces not to use weapons, except in cases of self-defence, armed clashes with “terrorist armed groups” or to prevent horrifying acts against, or mass killings of, citizens in areas where the security forces were present. In the Government’s opinion, the security forces carried out their duties with utmost professionalism, accuracy and self-control towards civilians while protecting their right to life from crimes committed by “terrorist armed groups”. 2. Human rights violations 26. OHCHR received information indicating that Government forces continued to commit numerous human rights violations during the period under review, including arbitrary arrest and detention, torture and other forms of ill-treatment in detention, sexual violence, extrajudicial executions and unlawful killings. Similar violations were reportedly committed against women and children. There were also increasing reports of abductions, torture and ill-treatment and murder of captured members of Government forces, proGovernment militia and civilians by anti-Government groups. Reports were also received of summary executions carried out by such groups of those in their custody after allegedly subjecting them to “speedy trials”.OHCHR received other information indicating that antiGovernment armed groups violated the rights to children, including by using children as soldiers. Other reports suggested that both Government forces and anti-Government armed groups had deployed snipers who targeted civilians. 27. In its note verbale dated 16 July 2012, the Government of the Syrian Arab Republic stated that it had taken measures to promote and protect the human rights of all Syrians, without discrimination based on race, ethnicity, colour, sex, religion or affiliation. 28. The Government also reported that, since the beginning of the crisis, it had carried out transparent, impartial and independent investigations into human rights violations to hold perpetrators to account and to provide remedies to victims. It referred to the 8