BEIRUT — Syrian government warplanes unleashed deadly airstrikes on rebel strongholds in the country's north on Tuesday, activists reported.
The barrage came as the U.N. food agency warned that more and more Syrians depend on assistance provided by the World Food Program to stay alive amid the worsening civil war.
The airstrikes hit Idlib and Aleppo provinces, with activists describing them as some of the worst since rebels fighting to topple President Bashar Assad made advances in the region in the past week.
Mr. Assad's regime increasingly has relied on warplanes in its struggle to crush rebels who have taken over large swathes of territory in the north and near the border with Turkey.
In addition to the air bombardment, Human Rights Watch on Sunday cited allegations that the Assad government has been using cluster bombs — which are banned by most nations. The New-York based group cited amateur video and testimony from Syrian front lines.
The Syrian military denied the reports, saying in a statement late Monday that the allegations were "baseless and are part of media propaganda that aims to divert international public opinion from crimes committed by armed terrorist groups."
Syrian authorities blame the civil war on armed gangs and terrorists carrying out a foreign conspiracy to destabilize Syria.
An activist in the northern province of Idlib, who identified himself only as Abu Hamza, declining to give his full name for fear of reprisals, said Tuesday's airstrikes were some of the worst since rebels took over the key city of Maaret al-Numan in Idlib on Oct. 10.
The city lies along the main highway connecting Aleppo with the cities to the south, including Homs and the capital Damascus.
Rami Abdul-Rahman, who heads the Britain-based Syrian Observatory for Human Rights, said the airstrikes were "concentrated and intensive" and the worst in weeks. He said warplanes carried out 12 raids in the area of Maaret al-Numan in one hour. The group relies on a network of activists on the ground.
Activists also reported casualties from the airstrikes, saying at least two children, aged 6 and 10, died in artillery shelling of the town of Kfarnebel in the Idlib countryside.
Fighting also continued in war-ravaged Aleppo, Syria's largest city and former business capital, and activists reported airstrikes in the town of al-Bab in Aleppo province Tuesday.
Activists say that more than 33,000 people have died in the Syrian conflict, which began in March 2011 as a peaceful uprising against Mr. Assad's regime but morphed into a bloody civil war.
In Geneva, officials from the World Food Program said some 1.4 million people required its assistance in September in many parts of Syria, adding that aid workers cannot reach all those in need because of the raging conflict.
"There are some areas that no one can reach," program spokeswoman Elisabeth Byrs told reporters.
Aid workers — including those from the Syrian Arab Red Crescent and local charities and nongovernmental groups — are unable to get to areas of Homs, Aleppo, Daraa and some rural areas around Damascus.
Ms. Byrs said the World Food Program also is planning to provide food to more than 460,000 Syrian refugees by the end of this year.
As of Tuesday, there were 343,871 Syrians formally registered as refugees or being helped by the U.N. refugee agency, spokesman Adrian Edwards said. The vast majority of them have found refuge in neighboring Iraq, Jordan, Lebanon and Turkey.