ICRC President Peter Maurer said during a Thursday briefing that fighting in Syria made it difficult to reach those in need of humanitarian aid.
"The humanitarian situation is getting worse despite the scope of the operation increasing," he was quoted the BBC as saying.
Maurer in September met with top government officials in Damascus, including Syrian President Bashar Assad and Foreign Minister Walid al-Moallem. Assad told Russian media Thursday he has no intention of leaving the country. The British government this week said it would consider finding a way to get Assad out of the country in order to advance political transition.
The BBC said it was unable to confirm reports saying government forces in Syria were taking control over more than 90 percent of the foreign medical assistance delivered to the country.
Members of the ICRC and Syrian Red Crescent have been killed in the line of duty during the Syrian civil war.
U.N. officials have said it's likely that both parties to the conflict in Syria have committed war crimes during the civil war, which began early last year.