ALEPPO — Four children, three boys and a girl, were killed on Wednesday morning while travelling to school in northwest Syria, along with a teacher, the UN Children’s Fund (UNICEF) said.

UNICEF Regional Director for the Middle East and North Africa, Ted Chaiban, said in a statement that they were victims of an attack on a market in Ariha, south of Idlib.

At least 11 people have been killed and 20 others wounded in a Syrian army shelling of residential areas of the rebel-held city, according to witnesses and rescue workers.

Artillery shelling was reported in Idlib on Tuesday also, the UN spokesperson Stéphane Dujarric told correspondents at the regular noon briefing. One civilian was killed, and four others injured.

The governorate is the last rebel held enclave in the country.

Artillery shelling was also reported in other parts of Idlib and in Western Aleppo.

Combined with Wednesday's attack in Ariha, the spokesperson described the recent escalation as "the most significant increase in hostilities in northwest Syria since the ceasefire agreement of March 2020."

"The UN condemns all violence in Syria", he added. "We remind all parties to the conflict to respect international humanitarian law, including the prohibition of indiscriminate attacks and the obligation to take all feasible precautions to avoid and minimize harm to civilians and civilian infrastructure."

The numbers of children injured and killed continue to increase, said Chabain, noting that earlier on Wednesday, a military bus had come under attack in the capital Damascus.

According to media reports, two explosive devices attached to the bus, detonated as it passed under a bridge in the centre of the city during rush hour.

At least 14 were reportedly killed, which the Sana State News Agency described as the deadliest attack in the Syrian capital in four years.

Around an hour after the Damascus attack, shelling by the Syrian army struck the rebel-held town of Ariha, in the northwestern region of Idlib.

The Syrian Observatory for Human Rights said the rockets struck a busy area at the time children were heading to school.

Three children were among those killed, the Britain-based war monitor said.

An AFP reporter saw at least five dead bodies as first responders treated the wounded and scenes of chaos filled the streets of Ariha.

"At 8 am (0500 GMT) we woke up to the bombardment. The children were terrified and were screaming," said Bilal Trissi, a father of two who lives nearby.

"We didn't know what to do or where to go and we didn't see anything because of all the dust around us," he told AFP. "They bombed us in our neighborhood and in the market. There are children who died and people who lost their limbs... We don't know why, what are we guilty of?"

“Today’s violence is yet another reminder that the war in Syria has not come to an end,” said the UNICEF official.

“Civilians, among them many children, keep bearing the brunt of a brutal decade-long conflict”, added Chabain.

“Attacks on civilians including children are a violation of international humanitarian law. Children should be able to reach their schools safely”, he underscored.

“We repeat our calls to those fighting, that children are not a target. They should be protected at all times especially in times of conflict.” — Agencies