CASTEL GANDOLFO, Italy: Pope Benedict XVI launched an urgent appeal for an end to bloodshed in Syria on Sunday, calling on the international community to do everything to help resolve the conflict.

"I continue to follow with alarm that tragic and growing episodes of violence in Syria with the sad succession of deaths and injuries," the pope said following his weekly angelus prayers at his summer residence near Rome.

"I renew an urgent appeal to bring an end to all violence and bloodshed," he said, calling for "no effort to be spared, particularly on the part of the international community, to reach a just political solution to the conflict."

The pontiff said his thoughts went in particular to the "huge number of internally displaced people and refugees in the neighbouring countries," and asked that they be guaranteed the "necessary humanitarian assistance and help."

A fierce battle between Syrian troops and rebel fighters raged in Syria's commercial capital Aleppo for the second day on Sunday, amid calls from peace envoy Kofi Annan for both sides to down weapons and find a political solution.

Human rights monitors say the conflict has killed more than 20,000 people since it erupted in March 2011.

In his speech from a balcony at the Castel Gandolfo near Rome, Benedict told hundreds of flag-waving pilgrims that he was also concerned about recent violence in Iraq, and prayed the situation in the country would stabilise.

"My thoughts also go to the dear nation of Iraq, which has been hit by numerous, serious attacks which have caused many deaths and injuries," he said.

"May this great country find the path of stability, of reconciliation and of peace," he added.

On Monday, 113 people were killed and over 250 wounded in the worst spate of violence to hit Iraq in more than two and a half years, which came after Al-Qaeda warned it would seek to retake territory.