(adds details from ICRC, UNICEF)
By Stephanie Nebehay
GENEVA, Aug 29 (Reuters) - Any escalation of the Syrian crisis following an apparent chemical weapons attack will aggravate civilian suffering, the International Committee of the Red Cross said on Thursday.
Areas plagued by heavy fighting, including the countryside around Damascus, eastern Aleppo and Deir Ezzor province, are already reeling from breakdowns of services such as water, electricity and garbage collection, it said in a statement.
The ICRC, an independent humanitarian agency, said it was appalled by reports of a poison gas attack on Aug. 21 and urged warring parties to respect the absolute ban on chemical weapons use under international law.
There are acute shortages of medical supplies, food and water in several areas in Syria cut off from aid supplies for months, according to the ICRC, which called for unconditional access to deliver relief supplies.
The Geneva-based ICRC has tried to reach civilians trapped in the old city of Homs since early July but it says it has been blocked by Syrian government authorities.
U.S. President Barack Obama told Americans a military strike against Syria is in their interest following last week's gas attack, in which hundreds of civilians were killed, and Britain said armed action would be legal, but intervention looked set to be delayed until U.N. investigators report back.
"Further escalation will likely trigger more displacement and add to humanitarian needs, which are already immense," said Magne Barth, head of the ICRC delegation in Syria.
"In large parts of rural Damascus for example, people are dying because they lack medical supplies and because there are not enough medical personnel to attend to them," he said, adding that some go hungry because food does not reach them regularly.
ICRC water engineers are trying to repair a damaged pipeline in Hama that serves some 1.3 million people, spokeswoman Dibeh Fakhr said. The pipeline in al-Waar, damaged in heavy clashes about two weeks ago, brings water from Homs to Hama.
The United Nations says that in the besieged areas of Damascus and Rural Damascus, 600,000 people are believed to be in a critical situation due to frequent power cuts, lack of water supplies and shortages of basic goods.
The U.N. Children's Fund (UNICEF) said on Thursday that partner agencies had reported water contamination in East Ghouta in the week before Aug. 20, prior to the alleged chemical weapons attacks in the area east of the capital.
"In most cases of localised water contamination, the cause is poor chlorination," spokeswoman Marixie Mercado told Reuters, adding that UNICEF did not have direct access to the area.
Local aid agencies had reported a rise in cases of typhoid fever in Ghouta but these reports were not confirmed, she said.
At least 100,000 people have been killed in the conflict that began in March 2011, and every day hundreds of people die or struggle with injuries, according to the ICRC.
The agency, which has 90 aid workers in Syria in its largest operation worldwide in budget terms, said it was committed to staying in the country provided it could carry out its work. (Reporting by Stephanie Nebehay; Editing by Alistair Lyon)