- 29 updates
US authorities are tightening up domestic security measures ahead of a possible military strike on Syria, according to CNN.
The FBI and the Department of Homeland Security are warning of a higher risk of cyber attacks after months of similar disruptions by hackers known as the Syrian Electronic Army.
One such attack brought down the website of The New York Times in recent days, and authorities say more attacks are likely.
The US Senate is to vote on a resolution authorising military force against Syria no later than week of September 9, the Senate majority leader Harry Reid told Reuters.
Mr Reid said the Senate would hold public hearings on the issue next week with senior Obama administration officials, and would hold classified and unclassified briefings for senators throughout the week.
"I believe the use of military force against Syria is both justified and necessary," Mr Reid said in a statement, saying President Assad had committed "atrocities" against civilians with a chemical weapons attack.
President Obama has sent a draft legislation to Congress formally asking for approval to use military force in Syria to "deter, disrupt, prevent and degrade" the potential for further chemical attacks.
President Obama has formally requested authorisation for military strikes on Syria from Congress, according to Reuters.
The draft bill would authorise Mr Obama to use military force on Syria as necessary to prevent more chemical attacks, the White House said.
The White House has released images of President Barack Obama meeting in the US Government Situation Room with his national security advisers to discuss strategy in Syria.
US Senators John McCain and Lindsey Graham have released a statement supporting President Obama's remarks on Syria.
In it, they said that they believed President Obama was right to say that the Assad regime's use of chemical weapons 'requires a military response by the United States and our friends and allies'.
The statement said anything less would "send the wrong signal to America's friends and allies, the Syrian opposition, the Assad regime, Iran, and the world".
They added that since Obama is now seeking Congressional support for this action, the Congress must act as soon as possible.
A rebel spokesman told NBC News:
US Secretary of State John Kerry spoke to the Syrian opposition leader to underscore the determination of the United States to hold the Syrian government accountable for using chemical weapons, a US official said.
Mr Kerry spoke with Syrian Opposition Coalition President Ahmed Assi al-Jarba to underscore President Barack Obama's "commitment to holding the Assad regime accountable for its chemical weapons attack against its own people on August 21st," a senior State Department official said.
Kerry also spoke with the foreign ministers of Saudi Arabia and Japan about Syria.
The US will not undertake military action in Syria before it is approved by a vote in Congress, Barack Obama said today.
Republican House Speaker John Boehner said the debate would likely take place on the week of September 9th.
Watch the President's speech in full:
Republican House Speaker John Boehner (R-OH), Majority Leader Eric Cantor (R-VA), Majority Whip Kevin McCarthy (R-CA) and Conference Chair Cathy McMorris Rodgers (R-WA) issued the following joint statement: