Syrian forces shelled several neighborhoods in Aleppo Tuesday, the 11th day of fierce clashes, as foreign jihadists poured into the country from Turkey. Scores of foreign jihadists from the Caucasus, Pakistan, Bangladesh and some Arab states -- some affiliated with al-Qaida -- were fighting alongside Free Syria Army troops, the British daily The Guardian reported Tuesday. The Syrian army stepped up efforts to drive rebel forces from Aleppo, the Lebanese newspaper The Daily Star said. In turn rebel forces vowed to turn the city into the "regime's grave." Valerie Amos a top U.N. official for humanitarian affairs estimated some 200,000 people have fled the city since intense fighting began, the Journal of Turkish Weekly said. Syrian opposition activists denied reports Syrian army forces had recaptured parts of the southwest sector of the city, The Daily Star said. The Syrian Observatory for Human Rights, based in Britain, said more than 100 people, the majority civilians, were killed Monday, The Daily Star said. The Syrian Network for Human Rights said numerous human rights violations were committed by Syrian army soldiers against civilians Monday, including what it described as the execution of at least 50 civilians in Yelda near Damascus.  The network said the bodies of two civilians turned up in debris in a Homs neighborhood that was shelled were burned, and reported a "massacre" in Daraa saying a makeshift hospital in a school was shelled, killing many citizens. After the shelling Syrian army soldiers entered the hospital and stabbed anyone who remained alive, the organization said.