The newly united group, called Syrian National Coalition for Opposition and Revolutionary Forces, is comprised of about 60 members -- representatives from each of Syria's major cities -- and has been signed by all opposition groups Sunday, The Sunday Telegraph reported.
"Everyone has signed our names to this," said Syrian dissident Yaser Tabbara, who helped shape the plan.
The deal was negotiated over the weekend between the Syrian National Council and other groups in Doha, Qatar, CNN reported.
On the streets of Syria, opposition forces are using barrel bombs to attack regime military positions, The Telegraph said.
"The regime was here yesterday," said Wassim, a rebel fighter said of a military post in Aleppo that was destroyed by 11 barrel bombs. "Now we are here."
And, as fighting intensifies along the Syria-Turkey border, 349 Syrians fled to Turkey Sunday morning, Today's Zaman reported.
Turkish officials registered the names of the new refugees before allowing them to enter Turkey, while health officials provided medical treatment to some of the refugees who were suffering from exhaustion.
Meanwhile, Britain's top general has suggested that his country could intervene militarily in Syria in the next few months, The Telegraph said.
Gen. David Richards, the chief of the Defense Staff, said it would be a "huge effort," adding, "The humanitarian situation this winter I think will deteriorate and that may well provoke calls to intervene in a limited way."
"But no, there's no ultimately military reason why one shouldn't and I know that all these options are, quite rightly, being examined. It's not impossible and obviously we develop contingency plans to look at all these things," he said.