The International Red Cross said Monday that it was seeking urgent clarification from Russia after its president was unable to enter the breakaway province of South Ossetia on a humanitarian mission.

Russian troops control access to South Ossetia, where fighting there has left thousands homeless and many dead and injured.

The Red Cross "has not been able to get access to South Ossetia," Dominik Stillhart, the International Committee of the Red Cross's deputy director of operations, said by telephone interview from Vladikavkaz, North Ossetia. "Access to South Ossetia is a priority. We have lined up teams, logistics and assistance. ... We need to have discussions in Moscow to find out exactly what is the problem."

Several NGOs have complained of difficulties in getting access to South Ossetia, where Russia's Emergency Situations Ministry has been coordinating a major relief effort.

ICRC president Jakob Kellenberger had hoped to lead a Red Cross mission to South Ossetia early Monday to bring in humanitarian help and assess the situation. But on Sunday evening the necessary permission did not materialize.

Kellenberger was seeking a meeting in Moscow on Tuesday with Foreign Minister Sergei Lavrov in order to clarify the situation and secure the necessary permission, Stillhart said.

The Red Cross said the humanitarian situation in Georgia appeared to be "much more desperate," with nearly three times as many refugees displaced by the conflict. "People in Georgia will need assistance for quite some time to come," Stillhart said.

On the other side of the border in Russia, about 25,000 refugees who streamed north out of South Ossetia in the wake of the fighting had started to return to the province, he said.