Shelling from Syrian rebels hits hospital in Aleppo, killing at least 4

April 28, 2016: In this image made from video and posted online from Validated UGC, a Civil Defense worker carries a child after airstrikes hit Aleppo, Syria. (AP)

Syrian opposition fighters launching rockets on government held-parts in the contested city of Aleppo struck a hospital, killing at least four people and wounding dozens more, a hospital official says, part of ongoing fighting that killed dozens of people Tuesday.

Syrian state TV said one of the rockets hit the Dubeet hospital in the central neighborhood of Muhafaza.

"Shells and mortar rounds are raining down on every neighborhood in Aleppo," Aleppo-based health official Mohammad Hazouri, speaking from Al-Razi hospital, told The Associated Press. He said four people were killed and more than 30 wounded in Dubeet hospital alone, adding that half the casualties at the hospital were women and children.

Syrian state TV said dozens of people were killed and wounded in the hospital attack, but did not give a breakdown of the casualties.

The Lebanon-based Al Mayadeen TV that has reporters in the government-held parts of Aleppo showed damage on both sides of the street in front of the hospital, which also appeared heavily damaged.

Cars in the street were scorched and some were turned over. The shops on the other side of the street showed moderate damage as smoke still climbed out of the wreckage.

Hazouri said the rebel bombardment of government-held parts of the city on Tuesday killed a total of 12 people and wounded more than 70.

The escalation came as the diplomatic focus moved to Moscow where the U.N. envoy for Syria started talks in efforts to restore a piecemeal cease-fire that would also include the contested northern city.

Staffan de Mistura is expected to push that the truce also covers Aleppo, which has seen an escalation in violence in recent weeks. De Mistura's meeting with Russian Foreign Minister Sergey Lavrov came a day after he met with U.S. Secretary of State John Kerry in Geneva.

In opening remarks in Moscow, de Mistura said "we need to make sure the cessation of hostilities is brought back on track."

Aleppo has been the center of violence over the past 12 days that left more than 250 civilians dead. The city was excluded from a truce declared unilaterally by the Syrian military last week for the capital, Damascus, and its suburbs and the coastal province of Latakia.

The Syrian military said in a statement it is repelling a wide scale attack on Aleppo launched by "terrorists" — a government term that includes all armed groups fighting President Bashar Assad's forces.

Tuesday's statement said the multi-pronged attack -- launched by armed terrorist groups, including Al Qaeda's branch in Syria, the Nusra Front, Ahrar al-Sham and the Army of Islam -- was preceded by heavy shelling of residential areas of the city.

"Our armed forces are currently working on repelling the attack and appropriately returning fire," it said.

Information Minister Omran al-Zoubi warned militants they will face harsh retaliation for the shelling of civilian areas, saying the government's "patience is running out and if they don't stop targeting civilians in the coming hours ... they will pay a high price."

The activist Britain-based Syrian Observatory for Human Rights confirmed the shelling of government-held parts of the city, and said that seven were killed in Tuesday’s attacks on Aleppo, including a child. The Observatory said more than 50 were wounded, including some who were in critical condition, which could raise the death toll.

Also in northern Syria, warplanes carried out intense airstrikes on the city of Raqqa, the de facto capital of the extremist Islamic State group, in the early hours Tuesday. Activist groups said it was not clear if the warplanes were Russian or those of the U.S.-led coalition.

The Observatory, which has a network of activists around the country, said there were more than 35 air raids and that 18 people were killed, including five members of the Islamic State group. It said dozens were wounded.

The anti-ISIS group Raqqa is being Slaughtered Silently said the airstrikes killed 10 and wounded dozens — but different casualty figures are common in the chaos of Syria's civil war. The group said there were calls from mosque loudspeakers for the residents to donate blood.

ISIS suffered major setbacks over the past months in Syria against government forces and U.S.-backed Kurdish fighters including the loss of the central historic city of Palmyra.

The Associated Press contributed to this report.