Strong words are coming from the Obama administration as the United States moves closer to a military response in Syria.
"There is no doubt who is responsible for this heinous use of chemical weapons in Syria: the Syrian regime," Vice President Joe Biden said.
White House press secretary Jay Carney said, "It's undeniable the chemical weapons were used on a large scale."
U.S. warships are in position, targets have been identified, and America's allies are standing by as growing evidence finds the Assad government guilty of using chemical weapons against his own people.
Now they await President Barack Obama's orders.
"We are ready to go," Defense Secretary Chuck Hagel said.
The White House is consulting with House and Senate leaders, and both the president and vice president have been on the phone with world leaders trying to gain full international support.
Key U.S. allies are on board for a military response.
"The question now for us is, are we more likely to deter the future use of chemical weapons by acting or not acting?" British Prime Minister David Cameron said.
Australian Prime Minister Kevin Rudd said, "The world cannot stand idly by in light of such a significant chemical weapons attack.
"If Bashar Assad didn't hesitate to use chemicals weapons against his own sleeping civilians -- what's to stop him from using them against sleeping Turks, Jordanians, or Israelis? So, that's the nightmare scenario," said Michael Rubin, a foreign policy expert with the American Enterprise Institute.
The Arab League released a statement holding Syria President Bashar al-Assad responsible for the attack and called on the United Nations to respond, but stopped short of calling for military action.
The United Nations is unlikely to give its support.
Still, White House officials say Assad's actions pose a direct threat to U.S. national security, giving Obama potential legal justification for launching a strike without U.N. approval.
The administration says this is not about regime change but about punishing the Syrian government for using such weapons against its own people.
"We cannot allow this kind of violation of an international norm to go unanswered," Carney said.
Meanwhile, a Syrian army officer says if his country is attacked "Israel will also be set on fire."
But Israeli officials said they're prepared to defend themselves, with Prime Minister Benjamin Netanyahu issuing a warning of his own to Syria.
"We are not part of the civil war in Syria, but if we identify any attempt whatsoever to harm us, we respond with great force," he said.
Israeli intelligence has evidence of intercepted conversations reportedly between Syrian officials talking about the use of chemical weapons.
"It does seem that some kind of substance was used," Lakhdar Brahimi, the UN's special envoy to Syria, said.
The looming threat of a chemical attack had jittery residents of Tel Aviv lined up for hours Wednesday at a gas-mask distribution center as the country called up reserve troops.
"We have two children and I'm afraid for my two children," Tel Aviv resident Galia Cohen said.
Reports indicate Syria is also preparing -- evacuating key military command centers and government buildings that could be on a potential U.S. target list.