U.S. lawmakers hailed the apparent liberation of Raqqa, Syria, as a major milestone in the fight against Islamic State, but cautioned that the terrorist group retains the ability to mount attacks in Europe and elsewhere, and that the ultimate defeat of IS will occur beyond the battlefields of Syria and Iraq.
"It's a great step in combating ISIS. Raqqa is definitely an important piece of real estate, as was Mosul [Iraq]," the chairman of the Senate Foreign Relations Committee, Tennessee Republican Bob Corker, told VOA. "It [Raqqa] was central to their caliphate, so very important."
"The concept has always been to eliminate the caliphate [that IS sought to build in the Middle East]," said the Foreign Relation Committee's top Democrat, Ben Cardin of Maryland. "Shrinking the caliphate, Raqqa falling is an important element in eliminating and containing ISIS. They lose a lot of their wealth and a lot of their credibility when they lose territory."
U.S.-backed Syrian Democratic Forces said Tuesday they seized the last remaining areas of Raqqa from Islamic State militants. The American-led coalition fighting IS said the city was "on the verge of liberation" after a protracted offensive that began in June.
Islamic State has also lost territory in neighboring Iraq, notably the northern city of Mosul, giving the group an ever-shrinking base of operations.
"For a while it’s been apparent that we were going to defeat Islamic State on the battlefield," said Senator Tim Kaine, a Virginia Democrat. "Their peak [at holding territory] was in August of 2014, and there’s been a steady erosion of them being able to control territory."
While welcoming the outcome in Raqqa and elsewhere, lawmakers cautioned that Islamic State remains a threat in many countries far beyond the Middle East.
"What we've seen is a diffusion [of IS elements], so they go to other countries and they do a lot on the internet," Cardin said. "To strike in Paris all you need is a couple people who get the opportunity and are motivated. That's a hard thing to eliminate."
"What they've been trying to do is more off-battlefield attacks here and there," Kaine said. "And what that does is put a primacy in this phase on intelligence sharing, because the way you stop the off-battlefield attack is through better and better intelligence-sharing. It makes alliances, like NATO and others, more important."
Corker said defeating IS militarily is "one element of multiple elements [of the coalition’s strategy] combating the ideology, suffocating them financially."
That more work remains to be done should not detract from progress made so far, according to Republican Senator Cory Gardner of Colorado.
"Our fight against ISIS will continue no matter where they are, no matter what they do, until they are eliminated," Gardner told VOA, using an acronym for Islamic State. "Any advance is significant and any defeat we give them is significant."