The Syrian army and its allies made sweeping advances in Aleppo on Monday, raining fire on rebels and pushing them to the brink of collapse in a shrinking enclave packed with civilians who said they faced «doomsday in Aleppo». «The bombardment did not stop for a moment overnight,» said a Reuters journalist in the government-held zone of the city, describing it as the most intense for days. Pro-government forces were clashing with insurgents in Fardous district, which was at the heart of the besieged pocket only days ago, after taking Sheikh Saeed in the south and Saliheen in the east, a rebel official said. «The situation is extremely difficult today,» said Zakaria Malahifji of the Fastaqim rebel group fighting in Aleppo. «People run from one shelling to another to escape death and just to save their souls... It›s doomsday in Aleppo, yes doomsday in Aleppo,» said Abu Amer Iqab, a former government employee in the Sukkari district in the heart of the rebel enclave. Tens of thousands of civilians remain in rebel-held areas, hemmed in by ever-changing front lines, pounded by air strikes and shelling, and without basic supplies, according to the Syrian Observatory for Human Rights, a British-based monitoring group. The Observatory said the Sheikh Saeed district had fallen to the army in fighting on Sunday night and early on Monday and troops were firing on the districts of Karam Al-Daadaa and Fardous. An advance into those districts would take the army into the heart of the area held by rebels as recently as Saturday, pushing them towards a last bastion of control on the west bank of Aleppo›s river and the area southwest of the citadel. The Observatory reported that the Daesh group carried out eight executions of Syrian soldiers and allied militiamen in Palmyra on Monday while warplanes bombarded their positions around the city. Another four people, including two children, were shot dead while the militants cleared the city of pro-government forces, it said. The Russian Defense Ministry said on Monday that 728 rebels had laid down their weapons over the previous 24 hours and relocated to western Aleppo. It said 13,346 civilians left rebel-controlled districts of Aleppo over the same period. The Observatory said that four weeks into the army offensive at least 415 civilians, including 47 children, had been killed in rebel-held parts of the city. Hundreds had been injured by Russian and Syrian air strikes and shelling by government forces and its allies on the besieged eastern part of the city. The Observatory said 364 rebel fighters had been killed in the eastern sector. It said rebel shelling of government-held west Aleppo had killed 130 civilians, including 40 children. Dozens had been injured. Opposition supporters have accused the government of mass arrests and extrajudicial killings, which Damascus has denied. The United Nations said last week it was concerned about reports that hundreds of young men had been detained upon leaving the rebel-held enclave. — Reuters