Both sides in Syria's conflict on Wednesday demanded an international inquiry into a deadly attack they each cite as evidence that the other has used chemical weapons.

Whereas, the United Nations said that Syria has made no formal request for a UN investigation into government claims. UN spokesman Martin Nesirky appeared to counter a statement by Syria's UN envoy Bashar Jaafari that Syria had asked for the "independent" inquiry into the claims. Nesirky said he had briefed Secretary General Ban Ki-Moon on Jaafari's comments to reporters. "I think we will have something further to say once we have received a formal request which we have so far not received," Nesirky told reporters.

Ban has been in touch with the head of the Organisation for the Prohibition of Chemical Weapons (OPCW), which implements the Chemical Weapons Convention, over the allegations. "The secretary general remains convinced that the use of chemical weapons by any party under any circumstances would constitute an outrageous crime," said Nesirky.The deaths of 26 people in a rocket attack on a northern town on Tuesday have become the focus of a propaganda war between President Bashar al-Assad's supporters and opponents, who accuse each other of firing a missile laden with chemicals.

The United States and Russia, which back opposing sides in Syria, took contrasting views of the strike on Khan al-Assal, near Aleppo, which, if confirmed, would be the first use of chemical weapons in the two-year-old conflict and could step up pressure for foreign military intervention. Robert Ford, the US ambassador to Damascus who left Syria more than a year ago, said his government had no evidence so far to substantiate reports that chemical weapons munitions had been used in Syria. "

But I want to underline that we are looking very carefully at these reports," he told a House of Representatives hearing.Ford warned of unspecified consequences for Assad's government if it were found to be using chemical weapons. Washington, which says Assad must be removed from power, has so far shunned direct military intervention in Syria.Russia initially backed the Syrian government's version, issuing a statement, expressing extreme concern about "the use by the armed opposition of chemical weapons". But on Wednesday, Moscow's line had softened. "There is no unequivocal evidence on this account yet," Deputy Foreign Minister Gennady Gatilov said on Twitter.

The opposition Syrian National Coalition said it wanted an international investigation into the alleged chemical attack in Khan al-Assal and on another in Otaiba, a town near Damascus. "The Coalition would like all parties and individuals involved in this reprehensible crime to be brought to justice," it said in a statement.Iran, Assad's closest ally, summoned the Swiss ambassador - who represents US interests in the Islamic Republic - to voice suspicions that the United States might be responsible if the rebels obtain chemical weapons. "

(Iran) emphasises the American government's responsibility in preventing rebels from acquiring and using chemical weapons," Foreign Ministry official Mohsen Naziri told IRNA news agency.The World Health Organisation said it would send medical supplies to Aleppo but could not verify if chemical agents had been used. Experts contracted by the U.N. agency will visit Aleppo health facilities to identify immediate health needs and provide support for treatment of toxins, it said.

Syria's military has turned increasingly heavy weapons on Assad's opponents, using firearms, then tanks, artillery, aircraft and long-range missiles, but it has denied it would use chemical weapons, if it had them, on its own people.David Friedman, a former specialist on weapons of mass destruction with Israel's Defence Ministry, said he did not believe chemical weapons had been used in the Khan al-Assal attack, citing witness testimony and television footage.Some of those hospitalised after the attack told a Reuters photographer of a strong smell of chlorine in the air and that many victims had fallen down dead after the blast.

Friedman said a rocket might have hit chemicals stored in the area. "As for the smell of chlorine, this could have been due to the indirect explosion of something containing industrial chemicals," he argued, saying this was common in urban combat.At least 70,000 people have been killed by conventional weapons in Syria's two-year-old conflict, but conflicting claims about chemical weapons are often bandied about.The US and Israel fret that Syria's presumed chemical arsenal might fall into the hands of militants fighting Assad, or be diverted to his Hezbollah allies.

The Syrian state news agency SANA said the government had sent two letters to the United Nations in the past voicing fears that hostile powers may supply chemical weapons to "terrorists" to fabricate claims that the government is using such arms. The Information Ministry has also said al Qaeda-linked Nusra Front rebels had previously seized a private factory in eastern Aleppo that had tonnes of poisonous chlorine material.On the other hand, Germany on Wednesday was prepared to take in another 5,000 Syrian refugees in the coming months in response to deteriorating conditions in the country.

Interior Minister Hans-Peter Friedrich said Berlin would grant asylum to 3,000 Syrians from June at the latest, followed by another 2,000 later this year in response to an "increasingly difficult" situation.On the battleground, at least three shells and several missiles fired in fighting in Syria landed inside Lebanon on Wednesday, residents and security sources said, but there were no reports of damage or injuries.

The area, in the northern part of Lebanon's eastern Bekaa Valley, is adjacent to Syria's Homs province, the scene of heavy fighting in recent months between rebels and regime forces. Embattled President Bashar al-Assad paid an unexpected visit to an educational centre in the capital Damascus on Wednesday. The visit appeared to be Assad's first public appearance since he attended prayers at a mosque in Damascus to mark the Holy Prophet’s (PBUH) birthday on Jan 24th.