奥巴马：叙利亚化学攻击值得“严重关切”
US President Barack Obama has said the alleged use of chemical weapons in Syria in an attack on Wednesday is a "big event of grave concern".
美国总统奥巴马称，本周三叙利亚发生的所谓的化学武器袭击是一件值得“严重关切的大事”。
Mr Obama said the US was still seeking confirmation such weapons were used, but if proved true the situation would "require America's attention".
Meanwhile, Syria's main ally Russia has said there is growing evidence that Syrian rebels were behind the attack.
The opposition says hundreds died in a government assault outside Damascus.
But despite calls from many different countries, there is no sign yet that the Syrian authorities will allow a UN inspection team to visit to investigate the claims.
Unverified footage shows civilians - many of them children - dead or suffering from what appear to be horrific symptoms as a result of Wednesday's attack.
Also on Friday, UN agencies said the number of children forced to flee Syria had reached one million.
The UN's refugee agency, UNHCR, and children's fund, Unicef, described the figure as "a shameful milestone", and said a further two million children were displaced within the country.
'Very troublesome'
Last year, President Obama said the use of chemical weapons in Syria would cross a "red line" and force a tough US response.
In an interview broadcast on CNN on Friday, he said that the recent claims of chemical weapons use were "very troublesome".
"What we've seen indicates clearly this is a big event, of grave concern, and we are already in communications with the entire international community," Mr Obama said.
He said that "core national interests" of the US were involved in the Syrian conflict, "both in terms of us making sure that weapons of mass destruction are not proliferating, as well as needing to protect our allies, our bases in the region."
The BBC has learnt that some in the White House are furious and regard Wednesday's attack as an outrage that breached international law and demands a response.