Last updated 1:25 pm (AEST) September 4, 2013
As the world waits for the US Congress to decide whether it will authorise military action against Syria in the wake of the alleged August 21 chemical weapons attack on the eastern outskirts of Damascus, the other pieces of the international puzzle continued to shift:
The speaker of the upper house of parliament, Valentina Matviyenko, told Vladimir Putin that MPs want to fly to Washington to lobby Congress against strikes.
The White House says there are no plans for a one-on-one meeting between Obama and Putin on the sidelines of the G20 summit in St Petersburg, scheduled to start on Thursday.
US President Barack Obama has won strong backing from key Republican leaders for military strikes against Syria, while Secretary of State John Kerry lobbied for support in the Senate.
Republican and Democratic leaders of the Senate Foreign Relations Committee have agreed on a draft resolution authorising military force in Syria that will be subject to a vote by the panel as soon as Wednesday US time.
The US public, however, remains deeply sceptical of US military action in Syria.
Israel carried out a joint missile test launch with the US in the Mediterranean Sea on Tuesday, raising regional tensions.
Earlier, President Shimon Peres recommended patience on US action, telling Army Radio: "I think it's permitted to carefully consider a decision beforehand rather than after, and I trust [Obama] on anything connected to Israel."
Caretaker Foreign Minister Adnan Mansour has told local media that the country's airspace will not be open for use.
Still, some airlines have adjusted their schedules to avoid night flights to Beirut.
Lebanese officials have expressed concern that any air strikes will send another wave of Syrians over the border.
"We've reached a very dangerous level of tension between refugees and host communities in every single spot in this country," said Ramzi Naaman, coordinator of Lebanon's refugee response.
The trans-Atlantic alliance condemned Syria's use of chemical weapons, but said its role would be confined to providing a forum for consultations and defending Turkey against possible spillover of the war.
"You don't need the NATO command-and-control system to conduct such a short, measured, tailored military operation," Secretary General Anders Fogh Rasmussen said in Brussels on Monday.
British Chancellor of the Exchequer George Osborne rejected the idea that further evidence provided by the UN may prompt another vote on action after last week's defeat.
"I think Parliament has spoken," he said. "I don't think another UN report or whatever would make a difference."
Both main candidates in Germany's September 22 general election, Chancellor Angela Merkel and Social Democrat challenger Peer Steinbrueck, ruled out a German military role in a televised debate on Sunday evening.
France's National Assembly is set to debate possible Syria action on Wednesday, but MPs are not scheduled to vote on a resolution. Under French law, Hollande does not need to call a vote until four months after any intervention has started.
"Zero hour for us begins with the first US cruise missile," Colonel Qassem Saadeddine, a member of the Free Syrian Army's high command, said. Members of the Free Syrian Army, or FSA, have been posted close to targets and received a consignment of rockets, machine guns and anti-tank weapons from "sisterly countries" (Gulf nations) in the past week that are enough to do the job, he said.
Not all government troops had moved out of the schools and other civilian areas they had moved into ahead of anticipated attacks on Saturday.
Kamel Wazne, an analyst at the Center for American Strategic Studies in Beirut, said Syria's military has been "militia-ised" – broken up into small mobile units that cannot be easily targeted by strikes.
Bashar al-Assad challenged the West to provide "the slightest proof" that he used chemical weapons against his people.
"Supposing our army wishes to use weapons of mass destruction. Is it possible that it would do so in a zone where it is located and where [our] soldiers were wounded by these arms, as United Nations inspectors have noted during visits to hospitals where they were treated? Where is the logic?" he asked in an interview with French newspaper Le Figaro.
Syria's civil war has driven almost a third of the population from their homes, said Antonio Guterres, calling it "a disgraceful humanitarian calamity with suffering and displacement unparalleled in recent history". New York Times, Telegraph, London, Washington Post, agencies
Sources: New York TImes, Telegraph, London, Washington Post, agencies