AKCAKALE, Turkey – Turkey sanctioned further military action against Syria on Thursday and bombarded targets across the border with artillery for a second day, raising the stakes in a conflict that increasingly is bleeding outside Syrian territory.

Although both sides moved to calm tensions, Turkey's parliament overwhelmingly approved a bill allowing the military to conduct cross-border operations into Syria – making clear that Ankara has military options that do not involve its Western or Arab allies.

It was the most dramatic escalation in tensions between the countries, which were close allies before the revolt against Syrian President Bashar Assad began in March 2011. Over the past 18 months, however, Turkey has become one of the strongest critics of the Syrian regime, accusing it of savagery and massacres against the opposition.