Obama made the case on Wednesday for a limited military strike against the Middle Eastern country in response to last week's chemical weapons attack even as he faced new obstacles with British allies and US lawmakers that could delay any imminent action.
Casting the need for intervention in Syria's civil war on the basis of US national security interests instead of humanitarian grounds, Obama presented his clearest justification to war-weary Americans for confronting Syrian President Bashar al-Assad's government with "international consequences".
While saying he had not yet made a decision on military action, Obama left little doubt that the choice was not whether to act but when to retaliate after last Wednesday's gas attacks, which killed hundreds of people in a rebel-held suburb of Damascus.
"We have concluded that the Syrian government in fact carried these out," Obama told PBS Newshour in a televised interview, saying it was now important to send a message that "it better not do it again".
There were growing signs, however, that the timeline for launching any military strike on Syria could be complicated not only by the UN weapons inspectors' continued presence there but by the Obama administration's efforts to co-ordinate with international partners and growing demands for consultation with US lawmakers.
Britain – a key player in any air assault on Syria – changed its stance on Wednesday, saying the UN Security Council should first see findings from international weapons inspectors and the UK Parliament would hold two votes before any military action is taken.
Errors from the Iraq war
Arguing for measured intervention after long resisting deeper involvement in Syria, Obama insisted that while Assad's government must be punished, he intended to avoid repeating Washington's errors from the Iraq war.
"I have no interest in any open-ended conflict in Syria, but we do have to make sure that when countries break international norms on weapons like chemical weapons that could threaten us, that they are held accountable," Obama said.
Despite opinion polls showing most Americans oppose deeper involvement in the Syrian conflict, Obama has been under pressure at home and abroad to enforce the "red line" against large-scale chemical weapons use he established just over a year ago.
He argued on Wednesday that a "tailored, limited" strike, not a protracted engagement like the unpopular Iraq war, could be enough to send a strong message that the use of chemical weapons cannot be tolerated. The likeliest option, US officials said, would be to launch cruise missiles from US ships in the Mediterranean in a campaign that would last days.
Obama cited chemical weapons dangers to US Middle Eastern allies Israel, Turkey and Jordan plus US bases in the region, and said America's national interests could be at risk if Syrian chemical arms fell into the wrong hands.
'Judge, jury and executioner'
Meanwhile, Chinese state media warned the West against strikes on Syria on Thursday as momentum mounted for Assad's regime to be punished over the attack.
In an editorial headed "No excuse for strikes", the state-run China Daily said the US and its Western allies were "acting as judge, jury and executioner".
"Any military intervention into Syria would have dire consequences for regional security and violate the norms governing international relations," it said, adding such a move "will only exacerbate the crisis and could have unforeseen and unwelcome consequences".
Making a comparison with the war in Iraq, it said the international community should not allow "itself to be led by the nose by US intelligence, which after all was responsible for claiming Saddam Hussein had weapons of mass destruction".
China is a veto-wielding permanent member of the UN Security Council, but the US has already said a proposed UN resolution that could have given an assault a legal foundation was going nowhere, blaming Russia.
In an unsigned commentary, the Global Times, which is close to the ruling Communist Party, added that Washington lacked "a clear political end goal".
"Citing 'moral obscenity' as an excuse to gear up for military action seems rash and hasty," it said.
Russia and Iran's aid to Syria
If strikes do take place, it added that "it is necessary for Russia and Iran to consider providing direct military aid" to Assad's government.
Beijing has called for a "cautious" approach to the crisis, with Foreign Minister Wang Yi backing a UN investigation to "find out the truth as soon as possible".
All parties "should avoid interfering in the investigation work or prejudging the results of the probes", he told the official Xinhua news agency Wednesday.
The foreign ministry has advised any Chinese citizens in Syria to leave as soon as possible.
Beijing said it opposes intervention in other countries' internal affairs and has previously attempted to block moves leading to military action in overseas conflict. – Reuters; AFP