During an exclusive interview on "This Week," Florida Republican Sen. Marco Rubio criticized President Obama for not intervening sooner in Syria's civil war, saying the inaction has led to the "worst possible scenario" in the war-torn country.

"It behooved us to kind of identify whether there was elements there within Syria fighting against Assad that we could work with, reasonable people that wouldn't carry out human rights violations, and could be part of building a new Syria. We failed to do that. This president failed to do that," Rubio told ABC News Chief White House Correspondent Jonathan Karl.

"The fact that it's taken this White House and this president so long to get a clear and concise policy on Syria has left us with the worst possible scenario right now," Rubio added.

"So now your options are quite limited. Now the strongest groups fighting against Assad, unfortunately, are al Qaeda-linked elements. That doesn't mean that they all are, but it certainly - this group has become the most organized, the best armed, the best equipped. Our options are now really narrower than they were a few months ago," he said.

ABC

The United States will provide arms to Syrian rebels after determining this week that the Syrian regime used chemical weapons. President Obama has said the use of such weapons would cross a "red line."

More than 90,000 people have died in Syria since March of 2011 according to the Office of the United Nations High Commissioner for Refugees, while the Obama administration estimates that 100 to 150 people have died from chemical weapons attacks in the country.

Rubio was also asked by Karl if he supported his own immigration bill, which he helped author with the "Gang of Eight" members in the Senate.

"Obviously I think it's an excellent starting point and I think 95 - 96 percent of the bill is in perfect shape and ready to go, " Rubio said. "But there are elements that need to be improved," citing the border security portion of the current bill.

The immigration bill currently in the Senate will need some Republican support in order to overcome a potential filibuster. Many in the GOP want to see the border security measures in the bill strengthened before they would consider supporting it.

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