DAMASCUS  - Rebels fighting to oust Syria’s President Bashar al-Assad on Wednesday announced plans to reform and stem the proliferation of militias, as they came under artillery and aerial attack on multiple fronts.

Assad himself came under renewed diplomatic fire from Turkish Prime Minister Recep Tayyip Erdogan, who said Syria had become a “terrorist state,” and from Egyptian President Mohamed Mursi, who told him to go.

Forces loyal to the embattled president again trained their heavy weapons on second city Aleppo, where the Syrian Observatory for Human Rights said 30 people, including seven children, were killed on Wednesday. In its latest toll, the watchdog said at least 90 people were killed nationwide on Wednesday - 64 civilians, 12 soldiers and 14 rebels.

The Observatory said fighter jets bombed zones controlled by the rebel Free Syrian Army (FSA) in the northern city while ground troops simultaneously unleashed a barrage of shells.

Aleppo has been the target of a five-week-old government offensive aiming to dislodge the rebels who took over swathes of the commercial capital in July.

Relentless bombardments and food shortages have been reported in zones still held by the rebels, a rag-tag army of military defectors and civilians who have taken up weapons.

A rebel general said on Wednesday that the FSA would soon adopt changes aimed at overcoming divisions and addressing the growing number of militias fighting on its behalf.

On the battle front, the insurgents attacked Hamdan military airport near Albu Kamal town in the eastern province of Deir Ezzor, the Observatory said.

Having failed to persuade the international community to impose a no-fly zone, the FSA has increasingly targeted airports used by regime attack helicopters and warplanes.

“Fighting has been going on for hours inside Hamdan airport between soldiers and rebels, who have taken over large sections of the site,” Observatory director Rami Abdel Rahman told AFP, adding that at least six rebels died in the assault.

In the central city of Homs, the rebel bastion of Khaldiyeh came under fierce mortar fire, and three children were killed when regime forces bombarded the Ariha area in Homs province.

UN and Arab League peace envoy Lakhdar Brahimi said on Tuesday that the death toll in the country was “staggering” and the destruction “catastrophic.”

Assad also came under fresh attack from Egypt’s president.

“I tell the Syrian regime ‘there is still a chance to end the bloodshed’. Now is the time for change... no time to be wasted talking about reform,” Mursi told Arab League ministers in Cairo.

Less stridently, China said it supported a political transition in Syria and defended its record during a visit by US Secretary of State Hillary Clinton.

Clinton reiterated she was “disappointed” by Chinese and Russian vetoes of UN resolutions that would have threatened action against Assad to end the spiralling bloodshed.

The United States, meanwhile, unveiled $21 million in new aid to help those caught up in the conflict, boosting its humanitarian funding to more than $100 million. While, UN Secretary General Ban Ki-moon sharply criticized the UN Security Council’s “paralysis” on Syria, warning it has hurt both the Syrian people and the council’s own credibility, addressing the UN General Assembly.