UNITED NATIONS/DAMASCUS - The United Nations will launch an investigation into the “possible use of chemical weapons in Syria,” Secretary General Ban Ki moon announced Thursday.

“I have decided to conduct a United Nations investigation into the possible use of chemical weapons in Syria,” the UN chief told reporters at UN Headquarters in New York.

The secretary-general said said the investigation will focus on “the specific incident brought to my attention by the Syrian government.” He said that his top advisers are still trying to determine the scope of the mission, the composition of the team and the steps required to guarantee the safety of UN personnel during their probe.

Their immediate task will be to investigate the possible use of chemical weapons in an attack Tuesday on a village near Aleppo. But Ban hinted that the team’s mandate could be broader, saying “there are other allegations of similar cases involving the reported use of chemical weapons.”

AFP adds: A suicide bomber targeted a mosque in central Damascus on Thursday, killing a senior pro-regime Sunni cleric, Syrian television reported, with a watchdog saying at least 15 people were killed.

“Senior cleric Dr Mohammed Saeed Ramadan al-Bouti was martyred in a terrorist suicide attack at the Iman Mosque in Mazraa in Damascus,” the channel said, adding that there were reports of more dead and wounded. The Syrian Observatory for Human Rights said at least 15 people were killed in the attack in addition to Bouti, with dozens more injured at the mosque in Mazraa district, just north of the city centre. A presenter on the channel said a suicide bomber had entered the mosque and blown himself up.

Bouti was the most senior pro-regime Sunni cleric in Syria, and his weekly addresses at Friday prayers were frequently broadcast live on state television.

Rebels have gained ground in the Golan Heights, which is partly occupied by Israel, launching coordinated attacks in the area and in nearby Daraa province, a watchdog said on Thursday.

“It appears that the rebels launched coordinated attacks on multiple parts of the Golan, taking control of areas and villages in the province of Quneitra,” Syrian Observatory for Human Rights director Rami Abdel Rahman told AFP.

Overnight, the Observatory said, “rebels took control of the Mashati al-Khodr and Dawar Khan Arnaba regions, as well as artillery bases” after heavy fighting in Quneitra province. Rebels seized an officers’ club in Jaline village, “after the withdrawal of soldiers,” while regime forces shelled the town of Sahem al-Jolan.

The offensive came as a security official in Damascus told AFP some 2,500 trained and equipped rebels had entered the Daraa region in recent weeks. The region borders Jordan, which the Damascus regime has accused of facilitating the flow of weapons and fighters. Earlier this month, the German magazine Der Spiegel reported rebels were being trained in Jordan by American specialists, a claim US officials have refused to comment on.

The Observatory said at least 43 people had been killed throughout the country on Thursday, including at least three people killed when a car bomb exploded in Homs province.

Human Rights Watch on Thursday urged US President Barack Obama on the eve of his Jordan visit to press King Abdullah II to accept Palestinian refugees and other asylum seekers at the Syrian border. “Jordan is routinely and unlawfully rejecting Palestinian refugees, single males, and undocumented people seeking asylum at its border with Syria,” HRW and Harvard Law School’s International Human Rights Clinic said in a statement.

HRW said while attention during Obama’s visit to Jordan on Friday and Saturday will focus on the 450,000 refugees that Jordan is hosting, Amman’s rejection of these categories of asylum seekers fleeing the violence should not be ignored.

President Bashar al-Assad on Thursday called the more than two-year deadly conflict in Syria a “battle of will and resistance,” in remarks published in newspapers. “Today, all of Syria has been wounded,” he was reported as saying on a visit the previous day to an educational centre in the capital.

“But what is happening cannot weaken us, and the battle is one of will and resistance. If we are strong, we will be able to protect the sons of Syria,” he said.

Media on Thursday reported the embattled Syrian leader as saying the conflict was “firstly a struggle against ignorance.” “Our message to our enemies is that we will turn Syria into a strong state that battles against ignorance,” he said.

The number of Syrians seeking asylum in developed nations tripled last year, the UN refugee agency said Thursday, amid an eight-per cent overall rise in people looking for a safe haven in rich countries.

Syrian asylum claims in 44 industrialised countries jumped to 24,800 from 8,400 in 2011, the year the civil war began. UNHCR however contrasted that with the number of Syrians fleeing to neighbouring countries, which has surpassed one million.

The United Nations estimates that more than 70,000 people have been killed in the Syrian conflict that began with peaceful protests in mid-March 2011 but quickly became an armed insurgency after a harsh regime crackdown on dissent.