SHARM EL SHEIKH, Egypt — UN Secretary General Ban Ki-moon said on Saturday he felt “shame” and “anger” at the international community's failure to end the Syrian conflict. “I confess to you my anger and my shame. Anger at observing the Syrian government, extremist and terrorist groups and terrorists relentlessly destroy their country,” he said. “Shame at sharing in the collective failure of international and regional communities to decisively act to stop the carnage that has afflicted the Arab brothers and sisters of Syria,” he told an Arab summit meeting in Egypt. Meanwhile, Al-Qaeda's affiliate in Syria, the Nusra Front, seized control of large parts of the northwestern city of Idlib from government forces on Saturday, sweeping into neighborhoods close to the city center, opposition activists and the group said. The Nusra Front is leading a group of rebels in a major offensive that began earlier this week to take Idlib, near the border with Turkey. If the city falls, it would be the second provincial capital and major urban center lost by President Bashar Al-Assad's forces in the four-year-old conflict. The eastern city of Raqqa fell to rebels, including the Nusra Front, in March 2013. It was subsequently taken over by Nusra's rival, Deash (the so-called IS), which has since declared it as its de facto capital. The Britain-based Syrian Observatory for Human Rights said rebel fighters seized control of most of Idlib in a push Friday evening and early Saturday after government forces withdrew to their bases and several other buildings in the city. The group, which relies on an extensive network of activists across Syria, said heavy fighting continued Saturday amid heavy artillery shelling from both sides. The Local Coordination Committees, another opposition activist collective in Syria, also reported the capture of large parts of Idlib by the rebels. In one video, also posted by Nusra on Twitter, a rebel fighter is seen tearing a billboard showing Assad in a suit and tie, with the words “Together, we protect it (Syria),” before trampling it with his feet. The video, which could not be independently confirmed, appeared consistent with AP reporting on events in Idlib. — Agencies