The international community has yet to come to a clear conclusion though speculation was still rife on the use of chemical weapons in Syria.

At the UN headquarters in New York, UN spokesman Martin Nesirky told reporters Tuesday that the United Nations does not have the agreement it needs for the UN fact-finding mission on the alleged use of chemical weapons in Syria, which is ready to deploy quickly to enter the country and do its on-site work.

"The Secretary-General has concluded that the mission should also investigate the facts related to the reported incident on Dec. 23, 2012 in Homs, not only the incident in Khan al-Assal," Nesirky said, stressing that UN Secretary-General Ban Ki-moon cannot accept engaging in a partial investigation.

The spokesman highlighted the need for on-site investigations and reaffirming the professionalism and integrity of the team, and characterized the Syria crisis as "an extremely bloody conflict which needs to end soon through a negotiated solution."

In Washington, U.S. President Barack Obama warned against rushing to judgment on the use of chemical weapons in Syria, saying he needs "hard, effective evidence" before taking further moves.

Addressing a press conference Tuesday at the White House to mark 100 days in office in his second term, the president also vowed to take "a spectrum of options" not applied before once he gets the facts.

"What we now have is evidence that chemical weapons have been used inside of Syria, but we don't know how they were used, when they were used, who used them," Obama said, adding "We don't have a chain of custody that establishes what exactly happened."

France was also "uncertain" about the Syrian government's probable use of chemical weapons in the country's violent civil war and was seeking more proofs.

"We have no certainty that the Syrian regime has used chemical weapons. There are clues that were given by the English, as the Americans. We are just checking that," French Foreign Minister Laurent Fabius?said.

"We asked the UN Secretary General to order an investigation, but Syria refused to receive investigators in its territory... So, we are developing our own means in a series of investigations...," he added.

The Syrian government, however, called for the deployment of the UN Mission to investigate the allegations.

Addressing at a press conference at the UN headquarters Tuesday, Bashar Ja'afari, the Syrian permanent representative to the United Nations, wanted the UN to fulfill the request of the Syrian government to "initiate an independent, genuine, technical investigation in Khan al-Assal," a village on the outskirts of Aleppo.

"We believe that the best way to reach a credible outcome through this mission can only be achieved through deploying without any delay the mission on the reported incident in Khan al-Assal," said Ja'afari.

"The Syrian government did not close the doors of the United Nations and the investigative mission to look into any other allegations, but the principle of respecting international law requires a strict respect for the sovereignty of member states," he said.

In Beirut, Lebanese Hezbollah leader Sayyed Hassan Nasrallah vowed Tuesday to defend the Syrian government, saying that the real friends of Syria would not allow it to fall.

He dismissed the recent Israeli and U.S. allegations that the Syrian forces had used chemical weapons in the battles, calling them a "game" aimed at finding an excuse for foreign intervention in the unrest-torn country.

At least 25 people were killed and 130 others wounded on March 19 when armed men fired a rocket stuffed with chemical materials at the Khan al-Assal town in Aleppo, the Syrian state-media said, accusing opposition fighters of being behind it.

However, the rebels denied the accusations and turned the accusation finger against the government.