U.S. President Barack Obama said on Wednesday that he has not made a decision about how to respond to the use of chemical weapons in Syria.

U.S. President Barack Obama speaks during a news conference at the White House in Washington D.C. on Aug. 9, 2013. [Xinhua]

Obama said he has not made a decision on how to respond to the chemical attack in Syrai in?an interview with the "PBS News Hour" at the White House.

But he said the international norm against the use of banned weapons needs to be "kept in place."

"We have concluded that the Syrian government in fact carried these out, and if that's so, then there need to be international consequences," he added. "I have no interest in any kind of open-ended conflict in Syria."

"I think it's important that if, we make a choice to have repercussions for the use of chemical weapons, then the Assad regime, which is involved in a civil war, trying to protect itself, will have received a pretty strong signal, that in fact, it better not do it again," Obama told the PBS.

Obama pledged a "limited, tailored approach" that will not draw the United States into the conflict, saying direct military engagement "would not help the situation on the ground."

"When you start talking about chemical weapons in a country that has the largest stockpile of chemical weapons in the world, where over time, their control over chemical weapons may erode, where they're allied to known terrorist organizations that, in the past, have targeted the United States, then there is a prospect, a possibility, in which chemical weapons that can have devastating effects could be directed at us," Obama said. "And we want to make sure that that does not happen."

U.S. House of Representatives Speaker John Boehner on Wednesday joined some of his peers by sending a letter to Obama, calling on the president to make his case for launching military strikes on Syria in response to the gas attack.

The top lawmaker demanded that Obama "make the case to the American people and Congress for how potential military action will secure American national security interests, preserve America's credibility, deter the future use of chemical weapons, and, critically, be a part of our broader policy and strategy."

Britain Wednesday went to the UN Security Council with a draft resolution that would authorize the use of military force against Syria. As expected, the five permanent members of the security council failed to reach an agreement as Russia reiterated its objections to international intervention in Syria.

U.S. State Department deputy spokeswoman Marie Harf says the US cannot be held up in responding by Russia's intransigence at the United Nations.

Russia says the use of force without a sanction of the UN Security Council is a "crude violation" of international law.?

An assessment on Syrian government's culpability is expected to be released by the American intelligence later this week.

According to?media reports that the military strikes under consideration will hit targets inside Syria, involving sea-launched cruise missiles or possibly long-range bombers.

Administration officials said the options aim not at toppling the Syrian government led by President Bashar al-Assad, but rather a direct response to the use of sarin gas last week.

The Syrian government and opposition, engaged in conflict since March 2011, have been blaming each other for the alleged use of the chemical weapons.

The alleged chemical attack in the suburbs of Damascus, capital of Syria, on Aug. 21, reportedly killed as many as 1,300 people.

(Xinhua contributed to the story)