German Foreign Minister Guido Westerwelle on Thursday asked Syria to grant full access to United Nations chemicals weapons experts to investigate the latest alleged use of chemical weapons by the Syrian government forces.

Westerwelle called for prompt clarification on the allegations and full access of the United Nations chemical weapons experts in the country to check these accusations.

"We are very worried about the reports that poison gas has been used near Damascus," Westerwelle said at a news conference. "These reports are very serious and if they are confirmed would be outrageous."

The main Syrian opposition group claimed that the Syrian government used chemicalweapons on Wednesday and killed as many as 1,300 people. But Damascus denied the accusations.

The UN Security Council on Wednesday underlined the need for "clarity" on the latest allegation, saying "the situation has to be followed carefully."

The Syrian civil war, which began in March 2011 between government forces and armed opposition seeking to oust President Bashar al-Assad, has killed more than 93,000 people and forced over 1.7 million people to flee the country.