At least 18 regime soldiers were killed during clashes Tuesday with rebels in the Karkameen area in the northern province of Idlib in Syria, activists said. Near the capital Damascus, the sound of heavy shelling echoed throughout the city, while activists reported that the regime's troops are carrying out random arrests in the rebellious area of Douma. Meanwhile, the London-based Amnesty International said Tuesday the Syrian regime may have committed crimes against humanity by using "lethal" force and "torturing" detainees in its crackdown on a 15-month-old uprising. "The pattern and scale of state abuses may have constituted crimes against humanity," Amnesty charged in its annual report. It said that while the UN Security Council referred Libya's former Leader Moammar Gadhafi to the International Criminal Court, it has failed to do the same with Syrian Regime's Leader Bashar Al-Assad. More than 12,000 people, mainly civilians, have been killed since the uprising began against Bashar Al-Assad, the Observatory said. Activists have reported that there are 100,000 detainees held in jails.