Obama, Russians Pressure Syria for U.N. Inspector Access

Reports: Syrians bury hundreds of victims in mass graves as the death toll rises.

President Barack Obama pauses speals about college financial aid at Henninger High School on Thursday, Aug. 22, 2013, in Syracuse, N.Y. (Jacquelyn Martin/AP)

President Barack Obama told CNN the alleged chemical attack is "very troublesome."

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A growing number of Western nations are pushing the Syrian government to help determine the source of a deadly chemical attack that by some accounts killed more than a thousand people earlier this week.

President Barack Obama and – in a shift – the Russian government have called on the Syrian regime to allow U.N. weapons inspectors already in the war-torn country to investigate the site of an alleged chemical attack in a suburb outside Damascus.

[GALLERY: Alleged Gas Attack in Damascus]

The U.N. inspection team, which arrived Sunday, has so far been blocked from accessing Ghouta, a suburb of Damascus, out of which has poured growing waves of photos and video depicting the corpses of local men, women and children.

"This is clearly a big event of grave concern," said President Barack Obama in a pre-taped interview with CNN released Friday.

An image provided by Shaam News Network allegedly shows several bodies being buried after a chemical weapons attack. The government has denied allegations.

The U.S. is trying to prompt better action from the U.N., he said, and has continued its calls on the Syrian government to allow the investigation of the site.

"This starts getting to some core national interests that the United States has," Obama said, pointing to the potential proliferation of Syrian President Bashar al-Assad's stockpiles of weapons of mass destruction, as well as the effects of Syria's instability on a region with U.S. allies.

[OPINION: Stay Cautious on Syria]

Obama had previously referred to Assad's use of chemical weapons as a "red line," but has not yet acted on his government's assertions that such attacks have taken place.

"The situation is very difficult," Obama told CNN. "And the notion that the U.S. can somehow solve what is a sectarian, complex problem inside of Syria is sometimes overstated."

"There is no doubt that when you start seeing chemical weapons used on a large scale ... it is very troublesome," he said, pointing to the ongoing investigation.

Syrian women attend a vigil against the attack outside the United Nations headquarters in Beirut, Lebanon.

The Russian state news service reported that senior officials are also pressuring Assad, a known ally, to grant access to the inspectors.

Russian Foreign Minister Sergey Lavrov and U.S. Secretary of State John Kerry said their countries have "common interest in carrying out unbiased investigation by U.N. experts who are currently in the country into the reports of the alleged use of chemical weapons near Damascus," reports RIA Novosti.

Russia has historically backed the Assad regime, and experts believe it continues to supply forces loyal to the Syrian government with arms and supplies. Russia has on multiple occasions parked its naval ships off the Syrian coast, though their true mission remains unknown.

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A statement from the Russian Foreign Ministry office said that Russia "called on the Syrian government to cooperate with the U.N. chemical experts," reports the New York Times. "It is now up to the opposition, which should guarantee safe access for the mission to the alleged place of the incident."

The U.S.-based activist organization Syrian Support Group estimates that 1,302 people died in Ghouta and almost 10,000 were victims of the chemical attacks. Its sources on the ground say as many as 1,488 have died as of Thursday evening, though those numbers are unconfirmed.

A man and woman mourn over bodies in Damascus.

"Many civilians were found simply unconscious in the street," reports SSG, which raises funds for the rebel movement using a rare license from the Treasury Department. There are strict laws restricting the U.S. government from openly aiding a rebellion such as these fighters in Syria.

Mohammad Salaheddine, an activist in Syria, told SSG that "the dead were loaded into large pick-up trucks by the hundreds and were taken to three large mass graves in Zamalka, Ain Turma and Arbeen. The bodies were placed inside, and dirt was bulldozed to bury them."