Sen. Marco Rubio, R-Fla., (left) and Sen. Bob Casey Jr., D-Pa., (right) announce Tuesday a new bill to provide nonlethal aid and training to vetted elements of the Syrian opposition. They spoke to reporters in the Dirksen Senate Office Building shortly before a subcommittee hearing on the humanitarian crisis in the region.  (Photo by Marshall Cohen/Medill) Sen. Marco Rubio, R-Fla., (left) and Sen. Bob Casey Jr., D-Pa., (right) announce Tuesday a new bill to provide nonlethal aid and training to vetted elements of the Syrian opposition. They spoke to reporters in the Dirksen Senate Office Building shortly before a subcommittee hearing on the humanitarian crisis in the region.
(Photo by Marshall Cohen/Medill)

WASHINGTON — Republican Sen. Marco Rubio and Democratic Sen. Bob Casey called Tuesday for increased assistance to the Syrian opposition, but stopped short of proposing arming the rebels, hours after the conflict’s first reported chemical weapons attack.

The pair proposed a bill that would provide nonlethal aid and training to vetted Syrian rebels fighitng President Bashar al-Assad. This month marks the second anniversary of the conflict, which started as a popular uprising and has claimed more than 70,000 Syrian lives.

“It’s in the national interest of the United States for Bashar al-Assad to leave,” Rubio said. “If you look at all these horrible terrorist attacks that have been carried out against our allies in the region. … Syria and the government of Assad is right in the middle of it.”

The proposed bill would also expand sanctions against the Central Bank of Syria and increase U.S. assistance to civilians by providing seed funding for a future reconstruction fund. Other lawmakers like Sen. John McCain, R-Ariz, support sending weapons to Syrian rebels; France and Britain have already announced plans to do so.

“We haven’t made nearly enough progress on this, what can only be described as a tragedy,” Casey said later at a hearing on the humanitarian crisis in the region.

The rebels and regime blamed each other Tuesday morning after an apparent chemical attack in Aleppo that killed at least 16 residents and injured dozens more. Witnesses saw people suffocating in the streets and smelled chlorine in the air.

President Barack Obama in December warned Assad against using his chemical stockpile, indicating it was a “red line” that would trigger U.S. intervention. Obama, as well as NATO and European Union allies, has not favored direct involvement in the bloody civil war but supported sanctions and pledged $60 million in nonlethal aid.

The main Syrian opposition group early Tuesday took a major step forward toward forming an interim government to serve areas under rebel control. Members of the Syrian National Coalition, meeting in Turkey, elected businessman and naturalized U.S. citizen Ghassan Hitto to serve as prime minister.

Syrian warplanes on Monday attacked areas in eastern Lebanon that host opposition hideouts. The cross-border action — the first such airstrike after two years of conflict — marked a “significant escalation” in hostilities, a State Department spokeswoman said.