Sept 4 (Reuters) - Here is a snapshot of Reuters news about the crisis in Syria:
* President Barack Obama issues a blunt challenge to sceptical U.S. lawmakers to approve his plan for a military strike on Syria, saying they would put America's international prestige and their own credibility at risk if they did not.
* U.S. Senate Foreign Relations Committee may delay a vote on an authorization for the use of military force in Syria that was expected on Wednesday, aides to committee members say, after some senators said they were unhappy with its wording.
* Russian President Vladimir Putin says U.S. Congress has no right to approve the use of force against Syria without a decision from the U.N. Security Council, and that doing so would be an "act of aggression". He also accuses U.S. Secretary of State John Kerry of lying to Congress about al Qaeda's role in the Syrian conflict.
* Putin says Russia may approve a military operation in Syria - if Damascus is proven to have carried out chemical weapons attacks, but he says such an operation could only be conducted with U.N. approval. At the same time, Putin says Russia will fulfill its arms contracts with Syria.
* Obama says he hopes Putin will change his position on Syria. "I'm always hopeful, and I will continue to engage him," he told a news conference in Sweden.
* Former Syrian Defence Minister General Ali Habib, a prominent member of President Bashar al-Assad's Alawite sect, has defected and is now in Turkey, a senior member of the opposition Syrian National Coalition tells Reuters. Habib would be the highest-ranking Alawite figure to break with Assad since the uprising against his rule began in 2011.
* The Syrian refugee crisis may worsen if there is no international reaction in response to the alleged chemical weapons attack last month, Turkey's Foreign Minister Ahmet Davutoglu says.
* Turkish Prime Minister Tayyip Erdogan reiterates that Turkey will take part in any international coalition against Syria, but stops short of saying whether that would include military action.
* France's Prime Minister Jean-Marc Ayrault says that if there is no response to the chemical attack in Syria it risks sending Iran the wrong message on its nuclear programme.
* British Prime Minister David Cameron says he believes the Syrian government will use chemical weapons against its own people again if the United States steps back from taking military action against it.
* The U.S. Congress, which votes largely along party lines on most issues, is displaying a different kind of split in the debate over Syria: Experienced lawmakers who support Obama's plans for military action are lining up against more skeptical and rebellious newcomers mostly from the ideological edges of both parties.
* Shifts of power and money - led by capital flight from emerging markets - and gaping divisions over Syria will test the resolve of G20 leaders when they meet in Russia's second city of St Petersburg this week.
* "My credibility is not on the line. The international community's credibility is on the line. And America and Congress' credibility is on the line, because we give lip service to the notion that these international norms are important." - U.S. President Barack Obama
* "Anything that is outside the U.N. Security Council is aggression, except self-defence. Now what Congress and the U.S. Senate are doing in essence is legitimising aggression. This is inadmissible in principle." - Russian President Vladimir Putin
* "The Middle East is a powder keg and the fire is approaching ... We shouldn't just talk about a Syrian response, but what will happen after the first strike. Everybody will lose control of the situation when the powder keg blows." - Syrian President Bashar al-Assad
* U.S. stocks rise as a rally in technology shares lifts the Nasdaq, though investors remain focused on whether there will be a Western-led military attack against Syria.
* Dollar hovers near a six-week peak against a basket of currencies, as encouraging U.S. economic data reinforces expectations that the Federal Reserve will cut back its stimulus this month. The greenback gained against the euro for a sixth straight session and was also sought for its status as a safe-haven on uncertainty surrounding a possible attack on Syria.
* Brent crude falls below $115 a barrel as prospect of an immediate U.S. military strike on Syria fades.
* Gold falls nearly two percent as investors cash in ahead of a crucial non-farm report that will give clues on the timing for the Federal Reserve's tapering, and on speculation that a U.S. strike on Syria is not imminent.
* Obama due in Russia for a two-day G20 summit that starts on Thursday. (Compiled by David Brunnstrom)