ISTANBUL -- Turkey's Parliament on Thursday authorized further military action against Syria as Turkish forces fired a second round of artillery across the border, threatening to escalate a confrontation that has highlighted Turkey's fraught double role as it tries to stay out of direct involvement in the fight against President Bashar Assad while offering safe haven and support to the rebels.
Turkey hit Syria after a mortar attack Wednesday that killed five of its civilians. But the strike was also a reaction to growing public frustration with Turkey's policy toward Syria -- which has done little to push Mr. Assad out, while bringing hardship to Turks, who have lost trade and have been forced to take in about 100,000 refugees -- and to the Turkish leadership's sense of having been left alone by Western allies to manage an increasingly combustible situation, experts and commentators said.
"I don't see what else the government could do," said Soli Ozel, an academic and a columnist, who said he viewed Turkey's response as one of restraint that made good on warnings that it would strike Syria if its border was threatened. "That is the least they could do. They have so tied themselves to massive retaliation rhetoric that they had to do something."
The Turks fired into Syria after weeks in which towns in southeastern Turkey had been hit by stray bullets and shells coming from Syria. The parliamentary measure, which was ratified after several hours of a closed-door session in the capital, Ankara, permits cross-border raids, although senior officials insisted that Turkey, a member of NATO, did not want a war with its Arab neighbor.
"Turkey does not want war with Syria," Ibrahim Kalin, a senior aide to Prime Minister Recep Tayyip Erdogan, wrote on Twitter. "But Turkey is capable of protecting its borders and will retaliate when necessary." In a separate message, he said that "political, diplomatic initiatives will continue."
In supporting the Syrian rebels by allowing weapons smuggling and the cross-border flow of fighters and refugees -- and enduring the spillover effects of economic collapse in border areas and errant munitions -- the government had little choice but to respond militarily, analysts said, even if the strike on Turkish territory was unintentional.
And ever since Syria downed a Turkish warplane in June, the government has been under domestic pressure to act.
"Many felt disappointed about the government's lack of action when Syria shot down a Turkish warplane in June and got away with it," said Nihat Ali Ozcan, an analyst at the Economic Policy Research Foundation of Turkey.
Given that fighting had been raging just across the border, some analysts said it was not surprising that munitions struck within Turkey -- which sent more tanks and antiaircraft weapons to the border Thursday -- and questioned the aggressiveness of Turkey's response.
The episode may also have pointed to Turkey's increasingly close relationship with the rebels. Though its military said it used radar to identify targets, rebels claimed Thursday that they aided the Turkish military in its targeting for the artillery strikes.