Washington ( CNN ) -- Former U.S. Secretary of State Hillary Clinton said Monday it would be an `` important step '' if Syria immediately surrendered its chemical weapons stockpiles to international control . `` But this can not be another excuse for delay or obstruction . And Russia has to support the international community 's efforts sincerely or be held to account , '' she said . A potential Democratic contender for president in 2016 who left the State Department in January , Clinton received questions and some criticism for not speaking out immediately after chemical weapons were allegedly used by the regime of President Bashar al-Assad last month . CNN Poll : Most Americans against U.S. strike on Syria . An aide said last week that she supported Obama 's decision to seek congressional authorization to punish Syria militarily , but she had not publicly weighed in until her appearance at the White House on Monday . Her comments came during an address on wildlife trafficking and followed a meeting with Obama . She adhered to the White House line on Russia 's proposal earlier in the day that Syria relinquish chemical weapons to international control to avert a possible U.S. military strike , which Obama is trying to get Congress to approve . Syria welcomed the proposal , paving the way for a possible diplomatic solution to the crisis that comes amid a two-year civil war in Syria that has killed more than 100,000 people , according to U.N. estimates . Clinton 's successor , Secretary of State John Kerry , discussed a similar scenario , though the State Department stressed that al-Assad could not be trusted to give up his country 's chemical stockpiles . And just moments before Clinton 's remarks , White House spokesman Jay Carney said the `` credible threat '' of a U.S. military attack on Syria led to the Russian proposal . But he said any such plan would require close evaluation and that Washington remained `` highly skeptical '' of the Syrian regime . Clinton said Syria 's alleged use of chemical weapons `` violates a universal norm at the heart of our global order '' and `` demands a strong response '' from the world led by the United States . House of Assad ' survives on loyalty , brutality . `` This world will have to deal with this threat as swiftly and comprehensively as possible , '' she said . Clinton did not say whether military action , as proposed by Obama , would be the best course . But she emphasized she will support the president and argued a `` political solution that ends the conflict is in the interested of the United States . '' She reiterated the White House 's notion that Russia 's proposal could have only taken place `` in the context of a credible military threat by the United States to keep pressure on the Syrian government . '' Behind the scenes , Clinton worked the phones for Obama , who is trying to convince Congress to go along with his plan for a limited , targeted military response . Clinton , a former senator , called Arkansas Sen. Mark Pryor over the weekend , a source familiar with the call confirmed to CNN . But Pryor had already made up his mind to vote against military action and announced his decision on Saturday . The source would not speak on the record because the phone call was private . A separate source familiar with the call confirmed Clinton also called Sen. Charles Schumer , D-New York , over the weekend . He already supported military authorization when the call took place . Clinton will likely repeat her White House comments during a speech Tuesday night at the National Constitution Center in Philadelphia , a Clinton source told CNN . In addition to pushing for diplomatic efforts to remove al-Assad from power , Clinton backed a proposal last year to provide weapons to Syrian rebels when she served as secretary of state . Clinton also issued warnings in January shortly before leaving office about Iran 's involvement in Syria , saying the country was providing al-Assad 's regime with military supplies . She urged Iran , as well as Russia , to reconsider their aid to the war-torn country . As Obama 's top diplomat during his first term , Clinton was automatically associated with the administration 's response to the Syrian civil war until she stepped down early this year . And she 's faced some criticism for that response as debates over Syria heat up in Washington . `` Had President Obama and then-Secretary of State Hillary Clinton acted then in support of pro-democracy forces when that rebellion was taking place , we could have removed Assad and helped usher in stability for that country , '' former U.S. Sen. Rick Santorum said in a statement last week . `` But we have a very different situation today . After nearly two years , 100,000 people killed , a rebel force comprised of al Qaeda and a Syrian regime in a much stronger position , a military strike would no longer be in our national security interest , '' the former Pennsylvania lawmaker said . Santorum is considered a potential candidate for the Republican presidential nomination in 2016 . Before leaving the State Department , Clinton defended her role in the situation . `` I 've done what was possible to do , '' she told reporters . Kevin Bohn , Catherine E. Shoichet , Jessica Yellin and Tom Cohen contributed to this report .
Clinton says a `` credible military threat '' keeps pressure on Syria . She says it `` would be an important step '' if Syria hands over chemical weapons control . She has been criticized for not speaking out about the situation earlier . NEW : Clinton helps Obama in outreach to senators on military authorization .