Russia's prime minister has said Syrian President Bashar al-Assad had made a "grave," and possibly "fatal" mistake by delaying political reforms and not speaking to members of the country's oppositon sooner.

"[Assad] should have done everything much faster, attracting part of the moderate opposition, which was ready to sit at the table with him, to his side," Dmitry Medvedev said according to the transcript of an interview with CNN released by his office on Sunday.

"This was his grave mistake, and possibly a fatal one," Medvedev said.

Medvedev’s comments are some of the harshest from Syria’s most important ally during the last two years of a civil war that began as an uprising against Assad’s rule.

Medvedev also said that Assad is losing his grip on power as the war, which has already cost more than 60,000 lives, continues.

"I think that with every day, every week and every month the chances of his preservation are getting smaller and smaller," Medvedev was quoted as saying.

"But I repeat, again, this must be decided by the Syrian people. Not Russia, not the United States, not any other country.”

In the remarks, made to the US-based TV network on the sidelines of the Davos World Economic Forum in Switzerland, Medvedev also placed equal blame for the escalation of the civil war on "the leadership of the country and the irreconcilable opposition".

'A terrible price' 

While inside Syria, rebels told Al Jazeera they stormed the train station in al-Kadam neighbourhood of Damscus taking weapons and injuring a number of army soldiers.

They reported fierce clashes with Syrian army troops in the area, including bombardment from government fighter planes.

While in the northern Idlib province, rebels say they have made gains capturing a government checkpoint seizing tanks, ammunition and armored vehicles

Sunday’s fighting came as United Nations humanitarian chief Valerie Amos arrived in Syria ahead of a UN aid conference in Kuwait which aims to raise $1.5 billion for millions of people made homeless, hungry and vulnerable by the 22-month-old conflict.

On Wednesday, Amos said Syrians were "paying a terrible price" for the failure of world powers to resolve the conflict, pointing to 650,000 refugees who have fled the country and the millions affected inside Syria.

"Four million people need help, two million are internally displaced and 400,000 out of 500,000 Palestinian refugees have been affected," she told the Davos forum in Switzerland.

The United Nations and aid groups inside Syria, including the Syrian Arab Red Crescent, could not keep pace with the rising number of people in need, she said.

"We must find ways to reach more people, especially in the areas we are still unable to get to, and where there is ongoing fighting," she said.

Source: Al Jazeera and agencies