Prime Minister Stephen Harper and U.S. President Barack Obama agreed today that Syria's recent actions call for a "firm response from the international community," as Western countries appeared to edge toward a possible military intervention against the regime in Damascus.

Chatting by phone on the escalating crisis, Harper "made it clear that he shares the view that the recent chemical weapons attack was carried out by the Syrian regime and described the use of these weapons as an outrage," a statement from the Prime Minister's Office said.

Both leaders concurred that the government of Syrian President Bashar al-Assad has appeared to try to "obscure evidence" of the attack, the statement said.

The phone call came as Canada's top general was in the Middle East meeting military chiefs from the U.S., Europe and several regional countries to discuss those possible responses, according to reports.

The two-day summit of military brass in Amman also included the chiefs of defence staff from Britain, the United States, Turkey, France, Germany, Italy, Saudi Arabia, Qatar and Jordan, an official source in Jordan's armed forces told the country's semi-official Petra news agency.

The Canadian government would not confirm that General Tom Lawson is attending the meetings. But various reports say the defence chiefs were discussing the threat to regional security posed by the ongoing civil strife in Syria, and in particular impacts on neighbouring Jordan, where 500,000 Syrian refugees have spilled over the border.

Jordan, a Western ally, would be particularly vulnerable if the Syrian army is in fact now using chemical weapons to suppress the 2½-year-old rebellion, as the U.S., Canada, Britain and Arab League affirmed this week.

What could Canada contribute? While France, Britain and the U.S. appear to be readying for a potential military offensive against the Syrian government, Canada has resisted offering more than humanitarian help. But if that changes, here's what the Armed Forces could theoretically contribute: HMCS Toronto, a navy frigate, is in the Gulf of Oman but could travel to the Mediterranean in several days. Its Harpoon missiles, normally for ship to ship combat, can be fired against shore targets.

C-17 transport aircraft — of which Canada has four, based at CFB Trenton in Ontario — could be used to ferry weapons and fuel to staging bases.

CP-140 Aurora patrol aircraft, used in the Libya mission, have top-notch radar and surveillance capabilities to help ID potential targets.

The Canadian Joint Incident Response Unit, a little-known special ops force, is trained specifically to capture and remove nuclear, chemical and biological weapons.

JTF2, the military's elite counter-terrorism force, could help pinpoint targets from the ground. –James Cudmore, CBC News

Jordanian Foreign Minister Nasser Judeh said the talks are looking at "scenarios on the ground, especially after the recent dangerous developments," according to the Agence France-Presse news agency.

AFP said Jordan expressed refusal to be used as a "launch pad" for possible military strikes on the regime of Syrian President Bashar al-Assad, consistent with Amman's long-stated preference for a diplomatic solution to the civil war, which has claimed 100,000 lives.

However, a report last week in France's Le Figaro newspaper said Jordan has helped the U.S. train hundreds of Syrian rebel commando fighters on its territory.

Canada has so far resisted any military assistance to the Syrian rebels or the prospect of partaking in armed strikes, preferring to offer humanitarian help.

Andrew MacDougall, the prime minister's communications director, repeated Tuesday that it is "premature to discuss roles" that Canada could play in an eventual military operation.

Opposition Leader Tom Mulcair said Monday he wants Parliament recalled before Canada commits to any armed intervention. He added that any military offensive against the Assad regime should be debated at the United Nations first.

"To see a government in the 21st century gassing its own citizens is an abomination and the world has to move against that, Mulcair said. "That should be done through the institutions of international law, in particularly the United Nations."

The Harper government is not legally obligated to obtain Parliament's consent to deploy the Canadian Forces against Syria, but the prime minister has previously promised to put all combat missions to a vote.

On Tuesday, a spokesman for Foreign Affairs Minister John Baird confirmed that the cabinet minister has spoken to Mulcair and Liberal Leader Justin Trudeau.

"I am certainly open to Parliament being recalled," Trudeau said Tuesday from Prince Edward Island, where he is set to attend a Liberal conference.

"What is happening over there is just horrific, the use of chemical weapons, most likely, against citizens, is something that one can't even imagine."

Trudeau didn't offer specifics about how he thinks Canada should proceed, saying "whether that goes as far as military involvement is uncertain at this point to me."

He said he believed Canada could play a "strong role" in governance and humanitarian aid in Syria, saying Canada has been "very, very helpful in terms of sending funds" but said he thought Canada could do more for refugees given the growing number of displaced Syrians.

In terms of possible military intervention, Trudeau noted that there are many unanswered questions and called for more dialogue about any possible action.

"Canada believes the only way to halt the bloodshed in Syria is through a political solution, however, we understand that this solution is becoming more and more difficult as the crisis enters a dangerous new phase," Rick Roth said in a statement.

He said Canada will continue to work with its partners to evaluate options, adding that it is premature to discuss recalling Parliament.

Canada will also have a chance to weigh in when NATO ambassadors hold their weekly meeting Wednesday, when they are expected to discuss developments in Syria.

"NATO has consistently expressed its grave concern about Syria's chemical stockpiles and any possible use of chemical weapons by the Syrian regime," a spokesperson for the military alliance said Tuesday. "The use of such weapons would be a breach of international law. We support the ongoing investigation by United Nations inspectors and will continue to review the evidence that is presented."