Syrian President Bashar al-Assad goes on American TV to warn Washington to brace for retaliation if US forces attacked his war-torn country.

Facing the most perilous passage of his presidency, Barack Obama is to redouble his efforts to persuade the American public to back strikes against Syria.

Prime Minister John Key strongly hinted yesterday that the Government would off the United States moral support for any punitive strike it took against Syria.

CNN aired graphic videos of victims that it said were shown to select US lawmakers as part of a push to shore up support for a strike on Syria.

The US tried to rally support this weekend for a military strike against Syria, running into resistance from the American public and sceptics in Congress and from European allies bent on awaiting a UN report about a chemical attack.

Tens of thousands of people filled St. Peter's Square for a four-hour Syria peace vigil, answering Pope Francis' call for a grassroots cry for peace that was echoed by Christians and non-Christians alike in Syria and in vigils around the world.

No matter which way you look at it, the decision was always a gamble.

The United States yesterday thanked New Zealand for its "strong and unambiguous stand" against the Bahsar al-Assad regime having used chemical weapons against the people of Syria.

The British statesman Lord Palmerston reckoned only three people had ever understood the Schleswig-Holstein question that caused several wars in the mid-19th century.

Prime Minister John Key spoke to British Prime Minister David Cameron last night about the chemical attack on civilians in Syria on August 21.

They're supposed to be talking about growth and money, but the threat of war in Syria is creeping into nearly every conversation as the leaders of the world's 20 top economies huddle in Russia this week.

Foreign Minister Murray McCully says the Opposition will be offered a formal briefing on Syria before any parliamentary motion is put by the Government.

US President Barack Obama has gained ground in his drive for congressional backing of a military strike against Syria, winning critical support from US House Speaker John Boehner.

'Fool me once, shame on you; fool me twice, shame on me" - so the British Parliament decided that it didn't want to be shamed over Syrian intervention, writes Gwynne Dwyer.

New Zealand has been asked to pledge moral support for a potential US military strike against Syria but the Government says it is yet to make any commitment.

The threat of Western intervention in Syria has markets on edge and looks set to add another layer of complexity to the global economic outlook, writes Liam Dann.

Edging toward a punitive strike against Syria, President Barack Obama said he was weighing "limited and narrow" action as the Administration bluntly accused Bashar Assad's Government of launching a chemical weapons attack that killed at least 1429 people.

The American and British governments should have seen this coming.

The US administration has bluntly accused Bashar Assad's government of launching a chemical weapons attack that killed at least 1,429 people - far more than previous estimates- including more than 400 children.

President Barack Obama yesterday prepared for the possibility of launching unilateral American military action against Syria within days as Britain opted out in a stunning vote by Parliament.

British PM David Cameron has lost a vote endorsing military action against Syria by 13 votes, a stunning defeat after his government was poised to join the US in strikes.

Al Jazeera correspondent Wayne Hay, formerly a TVNZ reporter, was arrested while covering events in Cairo on Tuesday along with three others, Al Jazeera reported.

Analysts believe Bashar al-Assad's regime is more likely to respond indirectly to any Western strike.