At least 22 people, including 14 children, have been killed by Syrian army air raids on rebel districts of the northern city of Aleppo, a rights group said.

"An attack using explosive-laden barrels over the Sakhur, Ard al-Hamra and Haydariyeh districts killed 22 people, among them 14 children and an 18-year-old boy," the Britain-based Syrian Observatory for Human Rights said of the assault on eastern Aleppo on Sunday.

Syrian activists said the armed forces used helicopters to drop barrels on the Ard Al-Hamra area of the city.

The Aleppo Media Centre (AMC), an activist network on the ground, reported several helicopter attacks on rebel-held areas of the city.

The Observatory also said the number of people killed in the town of Adra, northeast of Damascus, after a rebel faction attacked on Wednesday has risen to 28.

Observatory director Rami Abdurrahman said the dead were primarily members of President Bashar Assad's minority Alawite sect, as well as a few Druse and Shia Muslims. All three sects largely support Assad in the fight against the mainly Sunni rebels.

Meanwhile, UN officials visited Damascus to discuss how to help Syrians survive winter and the first United Nations aid flight from Iraq to Syria took off on Sunday after being delayed for several days owing to bad weather.

Desperate situation

Valerie Amos, who briefly visited Syria on Saturday, said the situation was desperate.

"I'm extremely concerned with what is happening as a result of winter, the impact that it is having on Syrians not just here but in neighbouring countries," Amos said.

"I saw the foreign minister and the deputy foreign minister. We were able to talk about some of the improvements that we have been able to see in terms of our co-operation."

The UN aid plane was expected to arrive in Qamishli in north-eastern Syria about 1300GMT, according to Abeer Etefa, senior Middle East spokeswoman for the UN World Food Programme.

"Over the next few days, we will be sending to Qamishli... 400 tonnes of food," Etefa told AFP news agency.

Laurent Fabius, foreign minister of France, spoke of his concern for the Syrian people, as he said he doubted whether a peace conference planned for Geneva next month would go ahead.

He warned that a failure to hold the meeting could mean more suffering for Syrians.

Al Jazeera