The International Committee of the Red Cross is trying to contact anyone with influence in Syria to achieve a ceasefire.
Its president is due to hold talks in Geneva with a senior official from the opposition Syrian National Council.
The ICRC has appealed to both sides to allow a two-hour truce each day to get vital aid to people trapped by fighting and to evacuate the wounded.
“Discussions have been taking place recently about this humanitarian pause, which would mean a cessation of fighting on the ground, so delivery of aid can be made possible because the security situation is difficult, and until now we have to wait and give a chance to the process,” said spokeswoman Carla Haddad Mardini.
Russia said it was working with the ICRC – the only international agency deploying aid workers in Syria – as well as the authorities and opposition to try to secure better security.
“Our initiative is aimed at providing security for humanitarian aid. We are actively working with Syria and neighbouring countries, so that the people don’t suffer from the ongoing violence,” said Foreign Ministry spokesman Alexander Lukashevich.
He said Moscow was against a French idea for humanitarian corridors, believing they might aggravate the conflict.
As President Assad’s forces continue to pound Homs, the ICRC has warned that people should not turn a blind eye to what is happening in other areas.