More than 50 countries have asked the United Nations Security Council to refer the Syria crisis to the International Criminal Court (ICC).
Switzerland sent the petition, on behalf of 56 UN member states, to the Security Council.
As Syria is not an ICC member, only a Security Council referral can start a war crimes investigation.
The signatories of the letter included European countries like Britain, France, and Germany.
Russia and China refused to sign the petition.
UN rights chief Navi Pillay said on January 14 that the Security Council must ensure that the Syrian government is held accountable for its alleged crimes.
The UN says more than 60,000 Syrians have died during the 22-month-long conflict.
Both the government of President Bashar al-Assad and the opposition have been accused of committing atrocities.
Meanwhile, Iran's Press TV quoted Iranian Foreign Ministry spokesman Ramin Mehmanparast as saying that Syrian Prime Minister Wael al-Halaqi will lead a high-ranking delegation to Tehran on January 15.
He did not provide any further details.
Halaqi's trip comes a week after the Syrian government freed more than 2,100 rebels -- a move that gained the release of 48 Iranians held hostage.
Iranian Foreign Minister Ali Akbar Salehi last week reiterated Iran's backing of Assad's government.
Salehi, speaking in Cairo, said a solution must be found to the Syrian conflict that excludes "foreign intervention."
Tehran has repeatedly called for a political solution and urged dialogue between Damascus and opposition groups.
Based on reporting by Reuters, AFP, and Press TV