Germany and France are to call on Wednesday for extending the suspension of Russian-led airstrikes against the besieged Syrian city of Aleppo at a crisis summit hosted by Chancellor Angela Merkel in Berlin.
Speaking as he left Paris for Berlin, Hollande pledged to do "everything possible" to prolong a suspension of the bombardment of Aleppo to allow humanitarian aid to reach some 275,000 people trapped in the city.
Hollande is to join Merkel along with Russian President Vladimir Putin and his Ukrainian counterpart Petro Poroshenko to discuss both the Ukraine conflict and the prospects for new sanctions against Moscow in the face of the bombing campaign in Syria.
Echoing the French leader's remarks, Merkel's spokesman Steffen Seibert said: "If possible, we need a sustainable ceasefire in Syria."
Syrian President Bashar al-Assad and his Russian allies have suspended bombardments of Aleppo ahead of a humanitarian pause announced for later this week.
"Quite frankly, we are going through a humanitarian crisis, a humanitarian catastrophe, that the world has not lived through for many years," said Rahed al-Saleh, who heads the White Helmets, a Syrian volunteer group that assists civilian victims of the country's civil war.
The evening meeting in Berlin was originally called to try to revive efforts to end the conflict in eastern Ukraine, which has raged since early 2014 and resulted in 9,500 deaths.
But Merkel said on Tuesday that she and Hollande would also confront the Kremlin leader over Moscow's military campaign in Syria and its bombardment of the city of Aleppo.
Both Berlin and Moscow have played down expectations for the meeting of the four leaders, in line with what most political analysts have said.
Two ceasefires brokered under the co-called Minsk accords have largely failed to end the fighting in the Ukrainian regions of Donetsk and Luhansk between Kiev military forces and pro-Russian separatists.
Kremlin spokesman Dmitry Peskov said Russia expected the summit to result in a constructive analysis of the situation in eastern Ukraine.
"The goal is to see where we stand and to determine what prevents us from the implementation of the Minsk agreement," Peskov said. "We do not expect a breakthrough," he said.
However, Merkel told a press conference on Tuesday that, in light of the suffering of the Syrian people, all options - including fresh sanctions against Russia as a result of its airstrikes - would also be the agenda in Berlin.
EU foreign ministers failed this week to reach an agreement on new sanctions against Russia in the wake of its bombing raids on the divided Syrian city of Aleppo as part of its military campaign supporting the Syrian regime.
The last meeting between the German, French, Ukrainian and Russian leaders on Ukraine was in Paris a year ago.
The EU joined the United States in imposing sanctions on Moscow following the Kremlin's annexation of the former Ukraine territory of Crimea in March 2014.
Wednesday's meeting will be the first time since the beginning of the Ukraine crisis that Putin has officially visited Berlin.