The strikes in Iraq targeted the Kurdistan Workers' Party, or PKK, whose affiliates have been effective in battling the ISIS group.
The Kurds of Syria and Iraq have become a major part of the war against the ISIS group, with Kurdish populations in both countries threatened by the militants' advance.
Syrian, Iraqi and Turkish Kurds took part in cross-border operations to help rescue tens of thousands of displaced people from the minority Yazidi group from Iraq's Sinjar Mountain in August last year and they continue to fight in cooperation with one another against the ISIS group in areas along the Iraq-Syria border.
They have been somewhat effective in limiting the expansion of the ISIS terrorists across northern Iraq but there are concerns that Turkish airstrikes on the PKK could jeopardize Kurdish positions.
Turkey is home to an estimated 15 million Kurds, about one-fifth of the country's population of 76 million. Most are Sunni Muslim.
In 2012, Turkey launched secret talks with the PKK's imprisoned leader, Abdullah Ocalan, to end the conflict. The talks were made public in 2013 and the PKK declared a cease-fire a few months later.
Kurds accused Turkey of not doing enough to help Syrian Kurds during the battle against so-called “Islamic State” terrorists over the Syrian Kurdish border town of Kobani, prompting violent clashes and straining the fragile peace process.
Five million Kurds have their own government in Iraq's semi-autonomous north and have significant representation in the central government with several key posts including the presidency, which is allocated to Kurds. They currently represent about 20 percent of Iraq's population, making them the largest ethnic minority.
The Iraqi Kurdish militia, known as the peshmerga, has been a major force in repelling the ISIS group's onslaught in recent months, with nearly a dozen countries rushing to its aid with weapons and training.
Meanwhile Kurds are the largest ethnic minority in Syria, making up more than 10 percent of the country's pre-war population of 23 million people. They are centered mostly in the impoverished northeastern province of Hassakeh, between the borders of Turkey and Iraq.
The Kurdish Democratic Union party, or PYD, is the most powerful political force among Syria's Kurds.
The People's Protection Units, known by its Kurdish acronym YPG, is the main Kurdish fighting force in Syria.
They have demonstrated a surprising resilience in their fight against ISIS terrorists group militants in Kobani, pushing them out in January.
More recently last month, they ejected the "Islamic State" terrorists group from their stronghold of Tal Abyad along the border with Turkey, robbing the ISIS of a key avenue for smuggling oil and foreign fighters.