BRUSSELS — NATO is ready to defend Turkey, the alliance’s top official said Tuesday, in a direct warning to Syria after a week of cross-border artillery and mortar exchanges dramatically escalated tensions between the two countries.
Ankara has sent additional fighter jets to reinforce an air base close to the frontier with Syria where shells killed five Turkish civilians last week, sparking fears of a wider regional crisis. Syria has defended its shelling of neighboring Turkey as an accidental outcome of its 18-month-old civil war.
The comments by NATO Secretary General Anders Fogh Rasmussen were the strongest show of support to Turkey since the firing began Wednesday — though the solidarity is largely symbolic.
NATO member Turkey has sought backing in case it is attacked, but despite publicly supporting Syria’s rebels Ankara is not seeking direct intervention. And the alliance is thought to be reluctant to get involved militarily at a time when its main priority is the war in Afghanistan.
‘‘Obviously Turkey can rely on NATO solidarity,’’ Fogh Rasmussen said ahead of a meeting of NATO defense ministers in Brussels. ‘‘We have all necessary plans in place to protect and defend Turkey if necessary.’’
When pressed on what kind of trouble on the border would trigger those plans, NATO’s chief said he could not discuss contingency plans. ‘‘We hope it won’t be necessary to activate such plans, we do hope to see a political solution to the conflict in Syria,’’ he said.
NATO officials said the plans have been around for decades and were not drawn up in response to the Syria crisis. They spoke on condition of anonymity because they were not authorized to talk to the media.
In an address to lawmakers from the ruling party, Prime Minister Recep Tayyip Erdogan of Turkey reiterated that Ankara will continue retaliating for attacks from President Bashar Assad’s regime in Syria.
‘‘Every kind of threat to the Turkish territory and the Turkish people will find us standing against it,’’ Erdogan said. ‘‘Soldiers loyal to Assad fired shells at us, we immediately reacted and responded with double force. We shall never stop responding.’’
At least 25 additional F-16 fighter jets were deployed at Turkey’s Diyarbakir air base in the southeast late Monday, Turkey’s Dogan news agency said, quoting unidentified military sources.
The military’s chief of staff inspected troops along the border with Syria on Tuesday.
But despite the flare-up in recent days, there appears little appetite in Turkey for a war with Syria, said Volker Perthes, the director of the German Institute for International and Security Affairs.
Only a sudden change in the situation on the ground could draw Turkey into what has remained a domestic conflict, said Perthes.
‘‘If the humanitarian situation becomes even worse, where you have more massacres, where at some point even the Russians wouldn’t block a UN Security Council resolution . . . then who could do the job of protecting civilians? It would be Turkey in the first place,’’ he said.
Joshua Alvarez, managing editor of the Istanbul-based Kalem Journal, said it was very unlikely that Turkey would call on NATO and force a decision on a commitment unless hostilities with Syria sharply increase.