Turkey's Prime Minister Recep Tayyip Erdogan has urged the international community to set up a humanitarian aid corridor to help civilians in Syria, while condemning Syrian president Bashar al-Assad for the bloody crackdown.

Erdogan told the ruling Justice and Development Party that Assad would be held accountable for the slaughter.

"His father was not held accountable for his actions in this world but his son will answer for the massacre," Erdoğan said. "The bloodshed in Syrian cities will not be left unaccounted for.

"Humanitarian aid corridors should be established immediately."

He said the international community should press the Syrian government to allow aid through particularly to the flashpoint city of Homs.

"The Arab League plan should be implemented without any more delay and further loss of lives," he said.

The Friends of Syria, a hub of about 70 nations that met in Tunis last month to plan a solution for the crisis in Syria, called on the Syrian authorities to allow "free and unimpeded access by the UN and humanitarian agencies". Latest reports indicate that the regime still refuses access for the Red Cross to the hardest-hit district in Homs of Baba Amr.

Erdogan has also indirectly criticised Russia and China, which vetoed a UN Security Council resolution in January.

"I am calling on the countries that remain silent on massacres in Syria and the international organisations that are unable to produce a solution: A single drop of an innocent child's blood is above every strategy," he said.