BEIRUT — President Mohammed Morsi of Egypt warned the Syrian president, Bashar Assad, on Sunday that ‘‘your time won’t be long,” as Syrian warplanes and artillery shelled the battleground city of Aleppo and opposition groups reported heavy fighting around the Euphrates River city of Deir el-Zour.
Morsi, an Islamist and Egypt’s first elected president, went after Assad just days after the top Syrian government spokesman said that the only change in Cairo since the ouster last year of Hosni Mubarak was Morsi’s beard. Morsi has called for nations to come together to support the Syrian opposition and end the bloodshed. His warning added to the acrimony in the region as the Syrian civil war continues to spill blood and pour out refugees.
In Ankara, Turkey, Wednesday, Prime Minister Recep Tayyip Erdogan said at a meeting of his governing party that Assad had made Syria a ‘‘terrorist state.’’
“The massacres in Syria that gain strength from the international community’s indifference are continuing to increase,’’ Erdogan said, according to Reuters.
Morsi, speaking at an Arab League meeting in the Egyptian capital, urged Assad to heed the lessons of recent history — the overthrow of dictators in Tunisia, Libya, Yemen, and Egypt. Step down while you can, he told Assad.
‘‘There is still a chance to stop the bloodshed,’’ Morsi said in the Arab League hall. ‘‘There is no room for stubbornness. Don’t listen to the voices that tempt you to stay.’’
The comments came just hours after the latest outbreak of violence around the Syrian Embassy in Cairo. More than 100 opponents of the Assad government had marched on the embassy to try to plant the flag of the Syrian rebels on the eve of the Arab League meeting. The Egyptian police fired tear gas in the clashes, and dozens of injuries and at least five arrests were reported.
Opponents of the Assad regime have ransacked the Syrian Embassy in Cairo at least twice since Syria’s uprising began 18 months ago, and its current facility is now hidden behind a black wall of steel.
In Syria, opposition groups said that artillery shelling by the Syrian military had destroyed buildings in several neighborhoods of Aleppo and had resulted in dozens of deaths. The Local Coordination Committees, an opposition group that tracks the violence, said the Aleppo death toll was at least 54. Activists distributed video footage said to show victims of the carnage. With independent journalists unable to work freely in Syria, such accounts cannot be confirmed.
‘‘We found 10 dead bodies under the debris of buildings that collapsed during the shelling, and 10 were found charred in another building,’’ said Majid Abdul Nour, an activist in Aleppo reached by Skype. ‘‘We couldn’t save them; they were burned.’’
He said that the Syrian air force was shelling several neighborhoods held by rebels on the eastern side of Aleppo, including Hanano, Bustan and Al Basha.
In the western part of the city, including the neighborhoods of Seif al-Dawla and Salaheddiin, Abdul Nour said that the Assad government was relying on artillery shelling instead of aircraft because Syrian Army forces were battling the opposition fighters block by block or building by building.
‘‘They are very close to each other, and that’s why the regime can’t use aircraft,’’ he said.
The artillery barrage came a day after an opposition military leader declared at a news conference in Istanbul that the fighters loosely allied as the Free Syrian Army now controlled more than 60 percent of Aleppo and had even set up checkpoints to consolidate their hold.
‘There is still a chance to stop the bloodshed. There is no room for stubbornness. Don’t listen to the voices that tempt you to stay.’
The Syrian Observatory for Human Rights, an opposition group based in Britain that also tracks the violence, reported heavy fighting around the city of Deir el-Zour. The group said that rebel fighters had taken control of parts of an airport there while fighting continued inside. The group also said that fighting had broken out near a security headquarters and that at least six Syrian government soldiers had been killed in the battle.
Other reports said that the rebels had taken control of a main road out of the city, northeast toward the town of Hasaka, where they were setting up checkpoints. But the Syrian air force was bombing the nearby town of Bukamal, at a pivotal border crossing into Iraq along the Euphrates. The rebels have at times closed the crossing there. The Local Coordination Committees put the death toll on Wednesday around Deir el-Zour at 16.
The Local Coordination Committees said that 20 people were killed on Wednesday in Damascus and its suburbs.
Residents said that the city’s amusements and movie theaters had all but shut down and that its cafes were keeping limited hours. Traffic moves at a crawl because of omnipresent checkpoints, and by 7 p.m. the streets are deserted. Families try to stay in their homes, and some stockpiled food in case of a shortage or a government road closing.
‘‘Damascus is dying very slowly,’’ one taxi driver said. ‘‘Damascus streets used to be filled by jasmine, damask rose and the branches of the Barada River. But today it is a garage of tanks and soldiers.’’