REPORT: Fighting and airstrikes near Syria's Aleppo kill at least 20

At least nine civilians, including three children, were killed by rebel fire in the government-controlled section of the divided northern city of Aleppo and airstrikes killed at least 11 in a town to the west, activists and government media reported Tuesday.

The Britain-based Syrian Observatory said at least 11 people, including five children, were killed when bombs were dropped in a market in rebel-held Atareb, west of the city of Aleppo. The activist-run Aleppo Media Center said the death toll was 20, posting pictures of destroyed buildings and civilians searching for survivors.

Violence has increased around Aleppo, including in neighboring provinces, since the government sealed off the final lifeline to rebel-controlled neighborhoods of the city. The rebels have launched a counteroffensive, clashing with government forces on a number of fronts. The United Nations said the encirclement of rebel-held areas of deeply divided Aleppo traps nearly 300,000 residents, making it the largest besieged area in war-torn Syria.

On Tuesday, residents of the rebel-held parts of Aleppo returned to burning tires, sending up big plumes of black smoke in the hope of preventing airstrikes.

But anti-government activists and residents reported that airstrikes and unguided barrel bombs hit various parts of the city. At least one person was killed in al-Sukkari neighborhood, according to the activist-operated Local Coordination Committees. On social media, rebel fighters asked residents to stay indoors and away from front lines.

The neighborhood is close to intense clashes pitting government and allied troops against rebels and Islamic militants who launched a counteroffensive on Sunday, hoping to ease the siege. Rebel spokesman Abdul-Salam Abdul-Razzek said there had been fierce fighting with government forces near al-Ramouseh, along a strategic government-controlled highway and artillery base south of Aleppo.

SANA reported on Tuesday that four women and three children were among the nine killed when rebels shelled and fired at three front-line neighborhoods on Monday night.

Meanwhile, a Syrian military official says the army repelled a rebel attack in Handarat, north of Aleppo. He spoke on condition of anonymity in line with regulations.