Iraqi Kurdish peshmerga fighters and moderate Syrian rebels bombarded Islamic State positions in Kobani on Monday, but it was unclear if their arrival would turn the tide in the battle for the besieged Syrian border town.

Kobani has become a symbolic test of the U.S.-led coalition’s ability to halt the advance of Islamic State, which has poured weapons and fighters into its assault of the town that has lasted more than a month.

The battle has deflected attention from significant gains elsewhere in Syria by Islamic State, which has seized two gas fields within a week from President Bashar al-Assad’s forces in the center of the country. […]