New York Times News Service

BEIRUT — As Syrian rebels and government forces clashed on the outskirts of Damascus, explosions rumbled in the distance and warplanes screeched overhead, the rebels appeared to be making their strongest push toward the city since the government repelled an offensive there in July.

A quiet tension prevailed downtown, but security checkpoints were proliferating and there were reports that President Bashar Assad was preparing loyal divisions to defend the capital, the heart of his power.

Military analysts warned that it was impossible to know whether a decisive battle for Damascus was beginning, especially as Syrians lost access to the Internet for 53 hours, limiting the flow of information, before it was restored Saturday. But they said that a government fight to defend its core in the capital could be the fiercest and most destructive phase yet of the 20-month conflict.

“We’re waiting for the big battle to begin,” said Emile Hokayem, an analyst based in Bahrain for the International Institute for Strategic Studies.