In Washington, State Department spokeswoman Victoria Nuland said the U.S. believes Turkey’s response was proportional and appropriate to ‘‘strengthen the deterrent effect so that these types of things don’t happen again.’’
Fawaz A. Gerges, head of the Middle East Center at the London School of Economics, said the latest violence shows just how easily the simmering tensions can ignite into a maelstrom.
‘‘For months, the two sides have been engaged in low-intensity warfare, and what we have seen is a dangerous escalation,’’ he said. ‘‘The potential for an all-out war is out there and there is no doubt that even though neither side wants it, a war could erupt because of a miscalculation on either side.’’
Syria and Turkey have a fraught history.
Turkey, which shares a 566-mile (911-kilometer) frontier with Syria, nearly went to war with its neighbor over Syrian support for Turkish Kurdish rebels in the 1990s. Turkey threatened military action in 1998, forcing Syria to expel Kurdish rebel leader Abdullah Ocalan.
The relationship improved dramatically over the past decade since Bashar Assad came to power in 2000 and the two countries reached out to build economic ties.
At the same time, Turkey, NATO’s biggest Muslim member, emerged as a regional power in the past decade, backed by a growing economy, emerging democratic credentials and historical and cultural links to neighbors. It pursued pragmatic links with authoritarian leaders, but shifted to a pro-democracy position as uprisings swept the Middle East and North Africa.
The crackdown in Syria is acutely uncomfortable for Turkey, which does not want to be seen as a bystander to atrocities on its doorstep. At the same time, it is wary of scenarios such as a ‘‘buffer zone’’ inside Syria that could plunge its troops into battles with Syrian forces, drag in other countries and undo its image as a regional mediator.
Turks have grown weary of the burden of involvement in the Syrian conflict, which includes the hosting of 90,000 Syrian refugees in camps along the border.
Yet Turkey is still unwilling to go it alone in Syria, and is anxious for any intervention to have the legitimacy conferred by a U.N. resolution or the involvement of a broad group of allies.
Turkey is mindful in part of inconclusive ground missions, mostly in the 1990s, against Kurdish guerrillas based in northern Iraq, as well as the bitter lessons of being seen as an occupying power that are associated with the U.S.-led invasion in Iraq.
Reaching deeper into history, Turkey is aware of Mideast sensibilities over Ottoman rule over much of the region.
The Syrian conflict has left Assad an international pariah, although Iran, Russia and China have stood by their old ally. On a visit to Pakistan on Thursday, Russian Foreign Minister Sergey Lavrov expressed his government’s concern over the escalation of tensions.
Speaking at a news conference in Islamabad, Lavrov said Syria has assured Russia that such an incident will not happen again.
‘‘It is of great concern for us,’’ Lavrov said. ‘‘This situation is deteriorating with every coming day.’’
Fraser reported from Ankara, Turkey. Associated Press writers Christopher Torchia in Istanbul, Elizabeth A. Kennedy in Beirut and Nahal Toosi in Islamabad contributed to this report.