US Secretary of State John Kerry stressed Monday the urgent need to return to a nationwide cessation of hostilities in Syria as escalating violence in many parts of Syria continued to spark concern.

The fighting in Syria is not only affecting civilians but also threatening United Nations-mediated efforts to broker a political end to the five-year conflict.

"The United Nations Security Council resolution calls for a full countrywide cessation and also for all of the country to be accessible for humanitarian assistance, obviously, that hasn't happened and isn't happening," he noted in a press stakeout outside a hotel in Geneva.

"In the last weeks the cessation of hostilities has been put to test, and frayed in certain areas, and fallen completely in a few areas," he added.

The truce, set-up by the International Syria Support Group with the United States and Russia as its co-chairs in February this year, is in a critical state following increased fighting in many parts of the country.

Civilians and healthcare workers have all too often been at the receiving end of shelling and bombing sprees, with both sides guilty of contributing to the raging chaos.

The upsurge in attacks targeting critical infrastructure such as hospitals and healthcare centers is also compounding the situation, particularly in the symbolically important city of Aleppo.

In light of violations, international powers are engaging in a desperate bid to restore a durable ceasefire to appease tensions and enable humanitarian aid to reach those most in need.

The restoration of the cessation of hostilities is also considered the only way to get peace negotiations back on track.

To date, no palpable progress has been made on the political front as proximity talks have faltered on a number of issues, including the deteriorating security situation on the ground.

Speaking after Kerry, UN Special Envoy for Syria Staffan de Mistura reminded that talks would make no progress as long as violations continue to take place.

"There can be no progress in the political process unless we urgently see tangible benefits on the ground for the Syrian people," he warned.

No date has been set for the next round of talks, though it is expected to be unveiled this month if the situation improves.

With progress on the political front contingent on the implementation of a durable truce, Kerry's efforts to instil a sense of urgency among those with regional influence come at a pivotal time.

Kerry arrived here in Geneva on Sunday for discussions with Jordanian Foreign Minister Nasser Judeh, Saudi Foreign Minister Adel al-Jubeir, and de Mistura to reaffirm the importance of the cessation of hostilities and seek more support for a political transition.

Kerry also said that discussions taking place Sunday touched upon how to separate al-Nusra from opposition fighters and how to stop fighting in Aleppo, adding that headway had been made in this regard.

The US diplomat further announced that he will speak with Russian Foreign Minister Sergey Lavrov on Monday afternoon, while the special envoy will meet with the Russian official in Moscow on Tuesday.

According to estimates, some 400,000 people have lost their lives in Syria since violence erupted in March 2011.

Millions more have been forced to flee their homes as a result of protracted violence and reigning insecurity.