Syria's alleged chemical weapons attack increases pressure on Obama administration

Updated at 3:22 p.m. ET

(CBS News) The Obama administration faced new pressure Thursday to take action on Syria.

Syrian forces launched more strikes Thursday outside Damascus. The attacks happened in the same area where rebels claim chemical weapons killed hundreds Wednesday.

CBS News' Margaret Brennan reports from the State Department that it is not yet possible to verify who carried out the attack or the type of toxic gas used that caused this mass killing, but it raises tough questions about whether any country will take action to stop it.

On Thursday afternoon, State Department spokeswoman Jen Psaki told reporters in Washington that President Obama directed the U.S. intelligence community to "urgently gather" information on the attack.

"Right now, we are unable to conclusively determine C.W. use, but we are focused every minute of every day since these events happened yesterday on doing everything possible within our power to nail down the facts," Psaki told reporters.

The White House confirmed that the president directed intelligence agencies to investigate the attack because of the alleged use of chemical weapons.

"The intelligence community is working to gather evidence and facts to ascertain what happened in Syria yesterday," an administration official said in a statement. "We don't speak to intelligence matters, so I don't have any additional details for you on that process."

Many images of what may be the world's most lethal chemical weapons attack in nearly 30 years are too graphic to show on network television.

Psaki said that between 1,000 and 1,800 people died in what Syrian activists described as a gas attack outside of Damascus.

(Watch at left a video obtained by the Syrian opposition that could not be independently confirmed showing a mother saying goodbye to her children who died in the attack)

The White House said Wednesday it was deeply "concerned" and called for an urgent United Nations investigation.

"Those who are responsible for the use of chemical weapons, if it's determined that that's what happened, will be held accountable," spokesman Josh Earnest told reporters Wednesday.

This alleged chemical attack took place nearly a year after Mr. Obama warned Bashar Assad that use of chemical weapons would change his calculus.

"That's a red line for us and that there would be enormous consequences if we start seeing movement on the chemical weapons front," Mr. Obama said.

When proof of Assad's chemical weapons use did emerge two months ago, the president promised to widen the scope and scale of aid to the armed rebels. Those weapons have not arrived, leading to more questions about the Obama administration's policy.

"I'm not talking about red lines," Psaki told reporters Wednesday. "I'm not having a debate or conversation about red lines, or I'm not setting red lines."

This week, the president's top military adviser, Martin Dempsey, said the Pentagon is not training any rebels.

In a letter to Congressman Eliot Engel, Dempsey said, "They must be ready to promote their interests and ours ... Today, they are not."

Engel, a Democrat, said there are military options, including missile strikes, that the administration should immediately consider.

"I think we have a lot of bad choices to make in Syria, and in my opinion standing on the sidelines really doing nothing is the worst choice that we can make," Engel said.

The Assad regime is winning the war with the help of Iran and Hezbollah, and now al Qaeda is in control of parts of Syria, but at this point the Obama administration assessment is that the threat does not merit U.S. military intervention.