"I emphasise this to Russia: The United States continues to believe there is a way forward that, although rocky and difficult and uncertain, can provide the most viable path out of the carnage," Mr Kerry said in an unusually heated showdown at the UN Security Council in New York.
"If we allow spoilers to choose the path for us, the path of escalation ... then make no mistake my friends: the next time we convene here we're going to be facing a Middle East with even more refugees, with more dead, with more displaced, with more extremists and more suffering on an even greater scale."
Mr Kerry said listening to Russia's Foreign Minister Sergei Lavrov made him feel like he was living in a "parallel universe" and he demanded that Russia and the Syrian Government immediately halt flights over Syrian battle zones.
He mocked what he described as absurd Russian explanations for an attack on an aid convoy on Monday that Washington says was carried out by Russian warplanes.
A Russian statement said the trucks had "caught fire", which Mr Kerry called tantamount to blaming "spontaneous combustion".
"The trucks and the food and the medicine just spontaneously combusted. Anybody here believe that?" Mr Kerry asked.
"To restore credibility to the process, we must move forward to try to immediately ground all aircraft flying in those key areas in order to de-escalate the situation and give a chance for humanitarian assistance to flow unimpeded."
Mr Lavrov, for his part, called for an independent investigation into the convoy attack, and said all parties needed to take simultaneous steps to stop the war.
The UN says it is gearing up to resume aid deliveries in Syria as fighting intensifies between rebels and pro-government forces on major frontlines near Aleppo and Hama.
"The preparation for these convoys has now resumed and we are ready to deliver aid to besieged and hard-to-reach areas as soon as possible," the UN Office for the Coordination of Humanitarian Affairs (OCHA) said in a statement.
"The United Nations continues to call for safe, unconditional, unimpeded and sustained access to all Syrians in need, wherever they are."
Aid deliveries in Syria were suspended after a deadly attack on a relief convoy near Aleppo two days ago left about 20 people dead.
On the ground, rebels battled the forces of President Bashar al-Assad on major battlegrounds, and air strikes reportedly killed a dozen people including four medical workers.
Local head of the Union of Medical and relief organisations Dr Ahmad Dbais said local doctors called for back-up when victims of the latest air strike started coming in.
"In this area all the time there is bombing, but at the same time many people live in this area," he said.
He said as many as eight his medical staff and four patients died — others were in a critical condition.
'We are at a make or break moment'
"We are at a make or break moment," UN Secretary-General Ban Ki-moon told the council, urging world powers to use their influence to help re-start political talks so Syrians can "negotiate a way out of the hell in which they are trapped".
The renewed battles on the ground demonstrated the thin prospects for reviving a truce that initially collapsed into fresh fighting and bombardments on Monday.
The Syrian Observatory for Human Rights, a monitoring body, said an air strike killed four medical workers and at least nine rebel fighters in the insurgent-held town of Khan Touman south of Aleppo, saying the rebels were part of the Islamist alliance Jaish al-Fatah.
The medical staff killed were working for the Union of Medical Care and Relief Organisations (UOSSM), it said. UOSSM confirmed in a statement that at least four of its staff had been killed.
Overnight fighting was focused in areas that control access to Aleppo city, where the rebel-held east has been encircled by government forces, aided by Russian air power and Iran-backed militias, for all but a few weeks since July.
Syrian state media and a TV station controlled by its Lebanese ally Hezbollah said the army had recaptured a fertiliser factory in the Ramousah area to the south-west of the city.
Rebels report 'very intense attack'
A rebel fighter in the Aleppo area said warplanes had been bombing all night in preparation for an attack. But "the regime's attempts to advance failed", said the rebel, speaking online from the Aleppo area.
A Syrian military source said insurgent groups were mobilising to the south and west of Aleppo, and in the northern Hama area.
"We will certainly target all these gatherings and mobilisations they are conducting."