By John Whitesides and Susan Heavey
WASHINGTON (Reuters) - President Barack Obama ramped up an intensive lobbying blitz on Monday to convince a skeptical Congress to support U.S. military strikes against Syria, even as lawmakers criticized the administration's approach and proposed alternative resolutions.
Obama planned six television interviews on Monday evening, and was due to visit the Capitol on Tuesday to speak directly to lawmakers before making a nationally televised address from the White House in the evening.
The intensifying public offensive comes ahead of a crucial Senate test vote expected on Wednesday on whether to authorize military action in Syria, in response to last month's chemical weapons attack against Syrian civilians.
As Obama pushed for domestic backing for action, U.N. Secretary General Ban Ki-moon said he was considering asking the Security Council to demand Syria move its chemical arms stocks to Syrian sites where they can be safely stored and destroyed.
Russia and Britain both supported that idea, which if successful might help defuse the crisis, but U.S. Secretary of State John Kerry, speaking in London, was skeptical.
Some members of Congress say Obama has lost support for a strike over the last week. Mike Rogers, the Republican chairman of the House Intelligence Committee and a supporter of strikes, said on Monday that Obama had "fumbled" the message on Syria and faced a critical moment.
"Mr. President, lay out the case. It's an important case for the future national security of this country. You're right on your decision, now show Americans why you believe it's right," Rogers said on MSNBC. "And when he does that, I think we're going to get votes."
Lawmakers from both parties worry even limited strikes could lead to another prolonged U.S. military commitment in the Middle East and spark a broader conflict.
Syrian President Bashar al-Assad tried to feed that fear on Monday, telling CBS television that a U.S. action would lead to reprisal strikes and unintended consequences.
If there are military strikes against Syria, the United States "should expect everything," Assad said. He said the repercussions could take different forms and include "direct and indirect" effects.
Assad denied there was any evidence linking his government to a suspected August 21 chemical attack near Damascus that U.S. officials say killed more than 1,400 people.
Obama administration officials say there is no doubt that Assad was responsible for the attacks. "We know that his regime gave orders to prepare for a chemical attack," Kerry said.
OUTCOME UNCERTAIN IN CONGRESS
A survey by USA Today on Monday found majorities of both the Senate and House remained uncommitted, complicating predictions about the outcome of the Syria vote.
A fraction of lawmakers - 22 senators and 22 House members - are on record as supporting strikes, USA Today said, with 19 senators and 130 House members saying they are against.
The Senate Foreign Relations Committee narrowly passed a resolution last week that prohibited the insertion of U.S. ground combat troops in Syria and limited the intervention to a maximum of 90 days.
But with the hunt on for more votes, other alternatives were being explored. Representative Chris van Hollen, a Maryland Democrat, said he was writing a resolution with Democrat Gerald Connolly of Virginia that would be more narrow than the Senate resolution.
He said the resolution would "make it absolutely clear that the only purpose of military action is to deter Assad from future use of chemical weapons."
Senator Heidi Heitkamp, a North Dakota Democrat, said she was working with Democrat Joe Manchin of West Virginia on an alternative that would give the Assad government 45 days to sign an international chemical weapons ban and begin the process of turning over its weapons.
"During this time, the U.S. would work to build international support and create a global response on the use of chemical weapons in Syria," Heitkamp said.
Ben Rhodes, deputy national security adviser, said the administration had been open to working with Congress on aspects of the authorizing resolution but lawmakers needed "to act with a sense of urgency."
"The votes will be there to act in the defense of the national security interests of the United States," Rhodes said on MSNBC, adding the videos of suffering victims of the chemical attacks that were distributed to lawmakers would help sway them.
Russia said on Monday it would urge Syria to put its chemical weapons arsenal under international control if that would avert military strikes. Foreign Minister Sergei Lavrov said he had conveyed the idea to Syria and expected "a quick and, I hope, a positive answer."
Kerry said Assad could avoid a military strike by surrendering all his chemical weapons within a week, but quickly made clear he had no faith that Assad would do so.
Asked by a reporter whether there was anything Assad could do to stop a strike, Kerry said: "Sure, he could turn over every single bit of his chemical weapons to the international community in the next week ... but he isn't about to do it and it can't be done."
British Prime Minister David Cameron said Syria should be encouraged to put its chemical weapons arsenal under international supervision, but said the world needed to ensure that discussion of such an idea did not become a distraction.
(Editing by David Storey)