A Syrian government air strike on a market in a rebel-held town has killed more than 20 people, activist groups say.

The air raid on Atareb, north of the city of Aleppo, also injured dozens of people, activists said.

Syria is engulfed in a three-year civil war, which has killed about 150,000 people.

Government forces have made gains recently, but rebels still control large territories.

Air strikes hit the busy vegetable market early on Thursday morning, the UK-based Syrian Observatory for Human Rights said.

The Observatory, which is close to the rebels, put the death toll at 27.

Meanwhile the Aleppo Media Center, an activist group, said that more than 20 people were killed in the air raid, AP news agency reported.

Video footage reportedly from the scene showed bodies lying among rubble and debris from the market.

Rami Abdel Rahman, who directs the Observatory, told AFP news agency all the people killed in the air strikes were civilians.

Abu Omar, a local activist, told the agency: "The area that was struck today is a market area, that's why there were so many civilians killed.

"The regime is hitting back against the civilians who support the revolt" against President Bashar al-Assad, he added.

Earlier this week, the Syrian government announced that it would hold presidential elections on 3 June, a plan denounced by the UN, US and EU.

UN Secretary General Ban Ki-moon has also accused both sides of "flagrant violations" of international law over the delivery of aid, preventing nearly 3.5m civilians access to vital aid and medicines.

BBC