Presidents Barack Obama and Bashar Al-Assad will go head-to-head in dueling US television interviews today in a crucial week for the US leader's push for air attacks on Syria.
Assad will reportedly deny that he used chemical weapons on civilians.
While Obama will push to reverse the nation's mood and win support for punishing the Damascus regime.
US Secretary of State John Kerry meanwhile is in London today in an effort to build diplomatic support.
Speaker of Syria's parliament - Mohammad Jihad al-Laham - says his country is being unjustly singled out:
President Obama's credibility is on the line as signs point to an uphill battle to win support for strikes in Congress.
He is to give interviews to six US television broadcasters today.
As he wages a political offensive of uncharacteristic intensity, chief of staff Dennis McDonough has acknowledged that the evidence linking Assad to last month's attack that allegedly killed 1,429 people is not "irrefutable."
"Do we have a picture or do we have irrefutable, beyond a reasonable doubt evidence? This is not a court of law. And intelligence does not work that way," McDonough told CNN.
Tomorrow the President will address Americans from the White House, ahead of a possible Senate vote on authorizing force in Syria later this week.
While the White House believes an endorsement from the Senate could be within reach, Obama faces a wall of opposition from both Republicans and from many of his Democratic allies in the House of Representatives.
US Secretary of State John Kerry has arrived in the UK, as he continues a European tour aimed at increasing support for military action in Syria.
Mr Kerry, speaking in Paris, said 12 countries are now prepared to take military action against Syria.