Russian President Vladimir Putin said the civilian toll in Gaza could see a "catastrophic increase" and warned of the risk of a regional war, after talking to Iranian and Arab leaders on Monday.
Russia has repeatedly called for talks on ending the conflict, which has strained relations with long-time partner Israel and complicated ties with Iran, which backs militant group Hamas.
The Kremlin said Putin had spoken to his Syrian, Egyptian and Iranian counterparts as well as Palestinian leader Mahmud Abbas.
Kremlin foreign policy aide Yuri Ushakov said Putin would also speak to Israeli Prime Minister Benjamin Netanyahu.
The Kremlin statement said Putin had voiced concern in his calls about "a catastrophic increase in the number of civilian victims and the aggravation of a humanitarian crisis in Gaza".
All the leaders called for "an immediate ceasefire and the establishment of a humanitarian truce to provide urgent assistance to those in need," it said.
Putin said he was ready to "coordinate efforts with all constructive partners to put an end to hostilities and stabilise the situation as quickly as possible".
The Russian leader repeated his call for the creation of a sovereign Palestinian state as the only way for lasting peace.
Fears for Palestinians trapped in the heavily bombarded Gaza enclave have grown since Israel prepared to launch a ground offensive aimed at killing Hamas leaders.
Israel declared war on the Palestinian Islamist group a day after waves of its fighters broke through Gaza's heavily militarised border and killed over 1,400 people, most of them civilians.
Hamas backer Iran has warned that an invasion of Gaza would be met with a response, prompting fears of a wider conflict that could draw in other countries.
Moscow, which has for almost 20 months been battling its own offensive in Ukraine, has repeatedly called for a ceasefire and offered itself as a mediator.