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President Obama will deliver a statement at 1:15 p.m. Saturday on Syria. A White House official says the president's remarks will not be about an imminent military operation in Syria, but will be an update to the public about his decisions on how to proceed.

ORIGINAL STORY ... After failing to win support from the United Nations and the British public for military action in Syria, the Obama administration is just now trying what some lawmakers say it should have been doing from the beginning -- making the case to the American people.

The president will deliver a statement at 1:15 p.m. Saturday on Syria.

A White House official says Obama's remarks will not be about an imminent military operation in Syria, but will be an update to the public about his decisions on how to proceed.

Polls suggest winning public support will be an uphill climb. A new Reuters’ poll shows U.S. support for intervention has increased over the past week to 20 percent, up from just 9 percent, with more than half of Americans opposing intervention.

Secretary of State John Kerry indicated Friday that the administration will try to convince the public and Congress that America has an 'obligation' to act.

“The president asked all of us on his national security team to consult with the leaders of Congress as well,” Kerry said. “I will tell you that as someone who spent nearly three decades in the United States Congress, I know that consultation is the right way for a president to approach a decision of when and how and if to use military force. … And I believe, as President Obama does, that it is also important to discuss this directly with the American people. That's our responsibility.”

However, Brendan Buck, spokesman for House Speaker John Boehner, said Obama still has a "responsibility to explain to Congress and the American people the objectives, strategy, and legal basis for any potential action."

The Reuters polls released Friday also showed support increased after the U.S. made public parts of a declassified intelligence report on Syrian President Bashar al-Assad’s alleged chemical gas attack last week in which 1,429 people were killed, including at least 426 children. In addition, roughly 53 percent of Americans surveyed said the U.S. should stay out of Syria's roughly 2-year-long civil war, down from 60 percent last week, according to the poll.

Obama's national security team is scheduled to talk about the issue Saturday with senators and Sunday with House members.

Also on Saturday, U.N. chemical weapons inspectors arrived in the Netherlands, where samples they collected in Syria will be evaluated in laboratories. The goal will be to check them for traces of poison gas that may have been unleashed in an Aug. 21 bombardment of a Damascus suburb.

U.N. spokesman Martin Nesirky said Saturday "whatever can will be done" to speedup the analysis, but he gave no timeline for a report on the results.

The inspectors left Syria early Saturday and flew out of Lebanon.

The team on Friday carried out a fourth and final day of inspection as they sought to determine precisely what happened in the Aug. 21 alleged chemical weapons attack near Damascus.

Tests on the samples are expected to take days, but U.N. disarmament chief Angela Kane is to brief Secretary-General Ban Ki-moon later Saturday on the investigation.

An Associated Press crew saw the U.N. personnel enter Lebanon from Syria through the Masnaa border crossing and then drive in a 13-car convoy to the Beirut airport. After four days of on-site inspections, the team wrapped up its investigation Friday into the suspected Aug. 21. chemical weapons attack. The experts took with them blood and urine samples from victims as well as soil samples from the affected areas for examination in laboratories in Europe.

Facing rising skepticism in Congress and abroad, the president and top Cabinet officials tried to make a robust case for intervention on Friday -- releasing an intelligence report showing "high confidence" the Assad regime carried out the strike and arguing that responding would be in the U.S. interest.

"This kind of attack is a challenge to the world," Obama said, adding: "A lot of people think something should be done, but nobody wants to do it."

He said his preference would be to form an international coalition to respond, but "we don't want the world to be paralyzed." Obama said he hasn't yet made a decision, but is considering a "limited, narrow act" to send a message about the use of chemical weapons.

The administration so far has failed to win over the U.N. Security Council, and British lawmakers on Thursday voted to reject any participation in a military strike. Obama and John Kerry, though, indicated they were prepared to move forward and downplayed the importance of U.N. authorization.

Obama charged that there is an "incapacity" at this point for the U.N. Security Council to act.

Hours before the U.N. inspectors pulled out of Syria, Kerry said the probe would not implicate anybody; only confirm whether the weapons were used.

"By the definition of their own mandate, the U.N. can't tell us anything we haven't shared with you this afternoon or that we don't already know," Kerry said.

Kerry was the most impassioned as he made the case for an unspecified intervention, saying there's "no doubt" the Assad regime was behind this "crime against humanity."

He cited the findings of the unclassified portions of the intelligence assessment, saying there's clear evidence chemical weapons were used by the Assad regime last week.

"I'm not asking you to take my word for it," Kerry said, urging people to read the report. "This is what Assad did to his own people."

Kerry called Bashar Assad a "thug" and a "murderer" who must not be allowed to escape retribution for the attack.

The assessment claimed that Syrian chemical weapons personnel even spent the three days prior to the attack preparing for the strike. The personnel allegedly were operating in a Damascus suburb from Aug. 18 until the day of the attack, near an area the regime uses to mix weapons like sarin gas. On the morning of the attack, according to the report, "a Syrian regime element" prepared for a strike, "including through the utilization of gas masks."

A senior U.S. official told Fox News that although the intelligence was obtained up to three days prior to the attack, the bits of intelligence gathered only made sense once the attack had been executed, meaning the U.S. knew of no advance warning of the chemical strike.

The report said the symptoms of victims -- "unconsciousness, foaming from the nose and mouth, constricted pupils, rapid heartbeat and difficulty breathing" -- as well as videos showing dead victims with no visible injuries are all consistent with chemical weapons use.

"We know where the rockets were launched from and at what time," Kerry said. "We know where they landed and when. We know rockets came only from regime-controlled areas and went only to opposition-controlled or contested neighborhoods."

Kerry said Friday the administration is mindful of concerns about an Iraq war repeat, but he said this would involve no boots on the ground and bear "no resemblance" to Iraq, Afghanistan, or even Libya.

"We know that after a decade of conflict the American people are tired of war. Believe me I am too. But fatigue does not absolve us of our responsibility," he said.

Meanwhile, U.S. Navy officials told Fox News that a marine amphibious ship, the USS Antonio, has now joined the U.S. destroyers in the Eastern Mediterranean.

Senate Intelligence Committee Chairman Dianne Feinstein, D-Calif., said she agrees with Kerry "that the world cannot let such a heinous attack pass without a meaningful response."

The Associated Press contributed to this report.