Many flights to Syria were cancelled Thursday as heavy fighting raged near Damascus airport, while two Austrian peacekeepers were wounded and activists said the nationwide death toll topped 70, dpa reported.
Damascus airport is located 27 kilometers from the centre of the capital, and the road leading to it passes through the rebel-held and embattled Eastern Ghouta region.
Flights from Dubai and Egypt into Damascus airport were cancelled, local activists told dpa.
"The road to Damascus international airport was closed because of ongoing fighting and military operations in the surrounding areas," said Britain-based group the Syrian Observatory for Human Rights.
Syrian forces had launched a major offensive on several areas near the airport, the group said.
However, Syrian information Minister Omran al-Zoghbi denied reports that the airport was closed, and that internet communication was cut off across the country. His comments, on Syrian television, caused panic among some Damascus residents.
Akamai, a US firm which monitor global internet traffic, reported that Syria was effectively offline.
In Vienna, the Austrian Defence Ministry said a convoy of its UN peacekeepers came under fire while driving to Damascus airport on Thursday, leaving two soldiers wounded.
The 170 soldiers in the convoy belonged to the UN troops stationed on the Golan Heights to monitor the border between Syria and Israel.
Ministry spokesman Michael Bauer told dpa it was unclear whether government forces or rebels fired the shots.
Meanwhile, the observatory said at least 10 people, among them women and children, were killed and 25 wounded, when Syrian planes struck the al-Ansari neighourhood in the northern province of Aleppo.
Earlier the watchdog reported that 15 people were killed in a raid at the outskirts of Aleppo, while opposition rebels announced they had taken control of an air defence base near the city.
"We are now controlling 65 per cent of the area, which stretches from Aleppo and reaches the Turkish-Syrian border," Abu Omar al- Halabi, a Syrian rebel commander in Aleppo, told dpa by phone.
Local activists said Thursday's death toll in Syria reached 71.
In the southern province of Daraa, a car bomb exploded near the house of a Syrian Baath Party official, killing him and three of his bodyguards, activists said.
News from Syria is hard to independently verify, as authorities have barred most foreign media from the country since a pro-democracy revolt started in March last year.
Meanwhile, New York-based Human Rights Watch on Thursday accused the Syrian opposition of using children as fighters.
"Children as young as 14 have served in at least three opposition brigades, transporting weapons and supplies and acting as lookouts," the watchdog said in a statement.
"Children as young as 16 have carried arms and taken combat roles against government forces," added the group.
Meanwhile, the international envoy for Syria, Lakhdar Brahimi, was due later Thursday to report to UN Secretary General Ban Ki-moon on his efforts to end the conflict, which the opposition says has now killed at least 39,000 people.
In Cairo, the newly created Syrian opposition coalition met for a second day in a row to discuss forming a transitional government.
But sources in the National Coalition of Syrian Revolutionary and Opposition Forces said disagreements had overshadowed the talks.
"There are still differences among the conferees over many issues including representation of minorities inside the coalition itself," an alliance member told dpa on condition of anonymity. "We need to put our house in order before we start talking about a government."
He added that there were "serious ideological differences" between rebels fighting inside Syria and most of the opposition figures who have long lived in exile.
The coalition, launched in Qatar on November 11, has been recognized by Britain, France, Turkey and the six-nation Gulf Cooperation Council.
Spain said it had also decided to recognize the bloc as the legitimate representative of the Syrian people.
The alliance is under pressure from foreign backers to unite the many opposition groups in exile and the rebels fighting inside Syria.