U.S. response to Kurdish advances in Syria tempered by caution

By Matt Spetalnick and David Alexander WASHINGTON (Reuters) - The Obama administration on Tuesday touted Kurdish-led advances against Islamic State in Syria as a model for the U.S.-backed effort to retake territory from the jihadist group, but U.S. officials cautioned that the insurgents remained resilient and could strike back. By highlighting battlefield gains in northern Syria by a reliable partner on the ground, the White House sought to further justify President Barack Obama's policy of limiting U.S. military involvement in the fight to reverse Islamic State's conquests there and in neighboring Iraq. But it was also a stark reminder of Washington's stumbling bid to turn moderate Syrian Arab rebels into a viable fighting force as well as a pointed message to the Iraqi government, which is struggling to rebuild its fragile military. Kurdish YPG-led fighters captured a town held by Islamic State on Tuesday, inching closer to Raqqa, the hardcore Islamist group's de facto capital of a self-declared "caliphate." The apparent blow to Islamic State's momentum there was achieved with the aid of stepped-up U.S. air strikes and intelligence sharing, U.S. officials said. The U.S. military had air-dropped weapons to YPG fighters inside Syria during an earlier campaign on the Turkish border. "This is, I think, an indication of how critically important it is for the United States to have a capable, willing and effective partner fighting ISIL on the ground," White House spokesman Josh Earnest said, referring to Islamic State by one of its alternative names. But U.S. officials, speaking on condition of anonymity, tempered that view, citing Islamic State's proven ability to adapt and quickly recover from setbacks. Kurdish forces, they said, may also need more time to consolidate their gains, "ISIL has proven a resilient force," a U.S. intelligence source said. "In the past, it has sought to offset losses with attacks elsewhere." Army Colonel Steve Warren, a Pentagon spokesman, said the Kurdish fighters' seizure of a north-south highway between Raqqa and the Turkish border would make it harder for Islamic State to keep up the flow of arms and foreign fighters into the heart of the territory it holds. But another U.S. official acknowledged that Islamic State had other routes and was not at immediate risk of being cut off. The capture of Ain Issa on Tuesday brought Kurdish forces and their allies within 50 km (30 miles) of Raqqa, but a YPG spokesman said an assault there was not currently "in our agenda." When asked whether Raqqa might be the next target, Warren told reporters in Washington: "We're not going to say specifically what our immediate plans are. Obviously our ultimate objective is to expel ISIL completely." Earnest credited the Kurdish-led gains in part to Washington having convinced Ankara last year to allow U.S.-armed Iraqi Kurdish peshmerga fighters to cross Turkish territory to help Syrian Kurds retake the border town of Kobani, a key defeat for Islamic State after it had seized a third of Syria and Iraq. It was unclear, however, how Kurdish forces in Syria were replenishing their arms supplies. Obama has ruled out sending advisers or trainers into Syria, where Washington shuns President Bashar al-Assad. But he has deployed a nearly 3,500-strong contingent in Iraq, where Islamic State recently captured the provincial capital of Ramadi. While Kurds have united against Islamic State, Washington faces a formidable challenge in Iraq of melding rival Shi'ite and Sunni Arabs into a fighting force. (Story corrects highway direction in ninth paragraph to north-south from north-west) (Additional reporting by Mark Hosenball and Steve Holland; Editing by Richard Chang)