Fighting in parts of Syria has morphed into local guerrilla wars, the Red Cross said Tuesday, where the number of prisoners remains unknown and 1.5 million people need help getting food, water, shelter, power and sanitation.

Fighting in the central city of Homs, where U.N. observers helped halt weeks of artillery attacks, and in the northern Syrian town of Idlib are now non-international armed conflicts, said Jakob Kellenberger, president of International Committee of the Red Cross.

"The type of the violence has changed a little bit," Kellenberger told a news conference at ICRC headquarters in Geneva. "At least in recent weeks, you have no longer these big battles like one had in Homs in the second half of February. You have more guerrilla attacks and bomb attacks."

Tens of thousands of people are living in public buildings or other people's homes, and the Red Cross and Syrian Arab Red Crescent is feeding about 100,000 "particularly vulnerable" Syrians, he said.

Kellenberger spoke ahead of international envoy Kofi Annan's assessment of the revolt in Syria to the U.N. Security Council later Tuesday.

He also said ICRC has gained permission to visit detainees at Aleppo's central prison from May 14-23 and is pushing for access to others.

What began as a largely peaceful protest movement has evolved into more Syrians taking up arms in the face of President Bashar Assad's violent crackdown on dissent. The U.N. says more than 9,000 people have been killed in the past 14 months since Assad, who inherited power from his father in 2000, began his crackdown.

The U.N., meantime, it is appealing for $27 million to quickly scale up aid.

"Our priority is to improve living conditions and to restore public services for up to 1.5 million people affected by the fighting," Kellenberger said. "Many people are still struggling just to make it through the day."

About 40 U.N. observers have been trying to restore calm, but so far the intervention by world powers has failed to deter the bloodshed. A larger force of 300 U.N. observers is being prepared to enforce the truce.

Officials are also concerned about Syrians flocking over the borders.

International Organization for Migration spokesman Chris Lom said Tuesday that 2,835 Syrians have registered at the Domiz refugee camp in northern Iraq since it opened this month and local authorities are expecting up to 7,000 more refugees at Domiz in the next month.