U.S. Secretary of State John Kerry and his Russian counterpart Sergey Lavrov called for a prompt start to the next round of Syrian peace talks to be held in Geneva on March 9 in a phone call late Friday. Kerry and Lavrov also reaffirmed the need for mutual cooperation to ensure the end of hostilities in Syria, according to a statement issued Saturday by Russia's Foreign Ministry.

"The sides spoke in favor of the earliest launch of United Nations-brokered talks in Geneva between the Syrian government and the entire spectrum of the opposition, during which the Syrians are to decide on the future of their country," the Russian ministry reportedly said, adding that the conversation was initiated by the U.S, according to Russian news agency Tass.

In Syria, rebels took advantage of the week-old ceasefire to stage peaceful protests against Syrian President Bashar Assad and demanded his resignation, while a top opposition figure told the Associated Press that his side believes it is "not suitable" for peace talks to resume in Geneva next week.

Despite the truce, Syrian military operations are still ongoing, detainees have not been released by Damascus and little aid is entering rebel-held besieged areas, Riad Hijab, who heads the opposition High Negotiations Committee, told the Associated Press, adding that the U.S. has "made many concessions" to Russia, one of the main backers of Assad.

Syria's conflict, which erupted in March 2011 as a popular uprising against Assad's authoritarian rule, quickly disintegrated into an all-out civil war which led to militant groups such as the Islamic State and the Nusra Front gaining control over large parts of the country.

The Geneva talks, originally slated to kickoff on March 7, were delayed by two days due to "logistical and technical reasons and also for the ceasefire to better settle down," the U.N. reportedly said on March 1.

Meanwhile, France's president François Hollande reportedly expressed optimism on Friday, saying discussions about a political transition in Syria would "accelerate" with the truce holding across the war-wracked country.