AMMAN, Jordan - Secretary of State John Kerry said Monday that it is clear Syria's Assad regime used chemical weapons last week and that President Obama believes such action should lead to consequences.
"President Obama believes there must be accountability for those who would use chemical weapons," Kerry said. "Nothing today is more serious."
Kerry spoke a day after the White House released a statement saying it has determined that images, witness reports and videos from the Damascus suburbs last week leave "little doubt" that chemical weapons were used, resulting in the deaths of hundreds of civilians. The president is considering military options, Secretary of Defense Chuck Hagel said Sunday.
That attack should "shock the consciousness of the world," Kerry said. "This is about the large scale indiscriminate use of weapons that the civilized world long ago agreed should never be used."
And the president believes that "no matter what you believe about Syria, you must stand up for accountability for the use of chemical weapons to make sure it's never used again," he said.
It is clear that the Syrian government is behind the attack because "we know" the Assad regime retains control over its chemical weapons arsenal and that it has the means to deliver those weapons, Kerry said.
Kerry said he watched some of the videos of the attack "one more gut wrenching time," Sunday night, after discussing the issue with the president's national security staff.
"As a father I can't get the image out of my head of a man holding up his dead child wailing with the chaos swirling around him," he said. "What is before us today is real and it is compelling."
And while investigators are collecting evidence at the scene of the site today, the U.S. government will be guided by the evidence it already has and by "conscience and common sense," he said.
Syrian opposition activists said Monday they would welcome military intervention in the war-torn country as the international community considers what action to take in response to a chemical weapons attack that reportedly killed hundreds of people last week.
Syrian President Bashar Assad "has used all kinds of weapons, chemical and cluster bombs, during massacres in Syria," said Abu Jaafar al-Mugarbel, an activist based in Homs, in western Syria.
"There is nothing that can stop the regime from doing that except military intervention. It is not the best way forward but there is nothing else after all that has happened."
A vehicle carrying U.N. chemical weapons investigators came under sniper fire Monday as it was heading toward the site of the alleged chemical attack. One vehicle was disabled, but no injuries were reported. The Syrian government accused the rebels of firing at the team, while a rebel representative said a pro-government militia was behind the attack.
Wassim al-Ahmad, a member of the Moadamiyeh local council, said five U.N. investigators eventually arrived at a makeshift hospital in the suburb where doctors and about 100 people still with symptoms from the alleged chemical attack were brought in to meet with the U.N. team.
The sniper hooting comes as U.S. naval forces move closer to Syria while Western powers discuss how to respond to the alleged chemical attacks. Russian Foreign Minister Sergei Lavrov warned that any military intervention in Syria without a mandate from the U.N. would be a grave violation of international law.
While the rebels are already receiving light arms from the West and from Gulf states, the opposition said they still don't want foreign troops on the ground but instead a no-fly zone to help them fight the regime as well as air attacks.
"First, hit military locations to stop missile attacks and air raids, which kill thousands of civilians," said Abu Rami, a 32-year-old anti-Assad activist in Homs. "But I'm against ground intervention in Syria to avoid what happened in Iraq. It is unacceptable for all Syrians."
The alleged chemical assault happened Wednesday on towns in Ghouta, which is east of Damascus.The humanitarian group Doctors Without Borders put the number of dead at more than 350. Syrians in the area claim more than 1,300 people died.
Images and videos have flooded the Internet showing children and adults suffering from symptoms including dilated pupils, increased paleness and shaking, that are consistent with chemical weapons. The images could not be verified by independent sources.
British Foreign Secretary of State William Hague has called for a "strong response" to the use of chemical weapons, and his German counterpart, Guido Westerwelle, said Germany would support any "consequences" of the attack.
But some activists said they were skeptical the international community would take the action needed to strop the violence.
"For two years, we have been hearing about a no-fly zone but it still hasn't happened," said Rami.
His comments were echoed by campaigners at Adopt a Revolution, an organization based in Berlin supporting revolutionary groups in Syria.
"The activists on the ground say, 'we are tired of asking the international community for anything because so far we haven't received anything,'" said Elias Perabo, spokesman for the organization.
"But more and more people are joining the Free Syrian Army to bring the conflict to an end because otherwise they will die."
While the U.N.'s Security Council has discussed the option of intervention in Syria, any decisions on action have been vetoed by Russia and China, who support Assad's regime.
The USA has provided unspecified military aid to Syrian rebels since it concluded chemical weapons had been used by the Syrian regime earlier this year. However, it has refrained from intervening further.
Even if the United States does decide to intervene, analysts said it was unlikely to be to a scale that would change the outcome of the conflict, which has seen more than 100,000 people die since it began in 2011.
"It's possible that we would see some kind of smaller-scale intervention, for example a strike at a missile-launch site or even a strike at the air force capability in Syria but beyond that, there is apparently no international appetite for any kind of ground intervention and I think that is the only thing that would have a chance at changing the outcome of the war," said Anna Boyd, deputy head of MENA forecasting at IHS, defense and security analysts, in London.
Still, members of the Free Syria Army, the group of ex-Syrian army members and others who are the main fighting force against Assad, say if there was any intervention, it would be for the U.S.'s own interests and not because the international community was trying to protect civilians.
"Despite the blockade of weapons, the FSA has made progress in the field and out putting Assad in the position where he needed to use chemical weapons," said Ibrahim Aslan, a spokesman for the FSA's force based near Latakia, in western Syria.
"This means that FSA has forced the U.S. to look at intervening militarily in Syria. But it won't do this to save the Syrians but only out of their interests."
U.S. defense officials told the Associated Press that the Navy had sent a fourth warship armed with ballistic missiles into the eastern Mediterranean Sea but without immediate orders for any missile launch into Syria.
Navy ships are capable of a variety of military actions, including launching Tomahawk cruise missiles as they did against Libya in 2011 as part of an international action that led to the overthrow of the Libyan government.