The minister told journalists in Lithuania that there was substantial evidence of Syrian President Bashar al Assad's responsibility for the attack, but underlined that an independent probe would be important for the international community.
"Therefore I think it is a good way to ask our colleagues in the United Nations to speed up the exploration of the inspection team. So my request is that we get as quick as possible the results of the inspection team that we have an independent statement by an independent neutral institution," Westerwelle, attending a meeting of EU foreign ministers in Vilnius, said.
In his words, the facts that the US, France, the UK, and Germany have allow to surely state that al Assad's regime used chemical weapons against its people.
"It is plausible that chemical weapons have been used in Syria, it is plausible that responsibility for this use of chemical weapons is on the side of the Assad regime," he said.
The United States suggests taking military action against al Assad's regime but Russia, having a veto right at the UN Security Council, does not support such a move.
The Syrian crisis will be on the agenda of the two day meeting of EU foreign ministers in Vilnius, starting on Friday and held under the Lithuanian EU presidency.
