DAMASCUS - Syrian troops mounted an assault on rebels near Damascus on Thursday, closing off the road to the airport before later securing it, authorities said, amid a widespread telecommunications outage.

Meanwhile, as UN envoy Lakhdar Brahimi hinted President Bashar al-Assad would have to step down to allow for a new Syria, a monitoring group said a government air raid on the northern city of Aleppo killed at least 15 civilians.

The Syrian Observatory for Human Rights said the army attacked rebel bastions in a string of towns along the highway and near the international airport, with state media saying the road was eventually secured.

Security forces were deployed after attacks on cars on the airport road by “armed terrorist groups,” state television said, using a term reserved for rebels fighting to overthrow Assad.

The fighting around the capital, which came after Internet links went down across Syria, caused EgyptAir and Emirates to announce the cancellation of flights to Damascus.

 The heaviest clashes erupted between troops and rebels in the towns of Babila and Hujaira southeast of the capital and in Harran al-Awamid, near the airport, the Observatory said, adding that army reinforcements were sent to the area.

Official media said several members of an “armed terrorist group, Al-Nusra Front,” had been killed in the town of Aqraba. Two Austrian soldiers with a UN force on the Golan were injured after their convoy was shot at on the road to the airport, the foreign ministry in Vienna said.

A ministry spokesman said one soldier was shot in the arm, and the other in the shoulder, but both were quickly treated by an accompanying doctor. As activists warned that sudden communication cuts are often a signal of imminent military offensives, US technology companies Akamai and Renesys, which monitor web traffic, said the country was cut off from the Internet.

“In the global routing table, all 84 of Syria’s IP address blocks have become unreachable, effectively removing the country from the Internet,” said Renesys.

In Damascus, users said both Internet and mobile telephone communications were cut and land lines barely functioning, with the country’s Internet provider citing technical problems. The state news agency SANA also had its feed interrupted at midday.

In northern Syria, five children and two women were among at least 15 people killed when a government warplane dropped two bombs on the rebel-held Ansari district of Aleppo, the Britain-based Observatory said.

The strike hit two buildings in Aleppo, the commercial capital, and videos posted online by activists showed the facades of several apartments blown away.

The videos, which could not immediately be authenticated, showed residents trying to rescue a wounded child and describing how barrel bombs were used. Also in the north, several rebel brigades attacked the fortress-like Wadi Daif army base in Idlib province, the Observatory said.

The Washington Post reported on Thursday that Syrian rebels have obtained up to 40 shoulder-fired anti-aircraft missiles, citing Western and Middle Eastern intelligence officials. Some of the missiles were supplied in the past weeks by Qatar, it said. Since the end of July, the regime has used its aerial superiority to try to suppress the growing insurgency.

On Thursday, it said 59 people died nationwide - 34 civilians, 19 soldiers and six rebels. On the diplomatic front, international envoy Brahimi briefed the UN Security Council, which remains divided between Western nations and Assad allies Russia and China on the 20-month conflict.

“I think it’s very, very, very clear that the people of Syria want change, and real change, not cosmetic changes,” he later told reporters in New York. “The new Syria will not look like the Syria of today.”

Brahimi also said that Syria “very, very urgently” needed a ceasefire and a large peacekeeping force. “A ceasefire will not hold unless it is very, very strongly observed. That, I believe, will require a peacekeeping mission.”

Spain on Thursday announced its recognition of the Syrian National Coalition as the legitimate representative of Syria’s people.