The top US diplomat, touring the Middle East to establish a coalition of more than 40 countries, was meeting with Turkey's leaders including President Recep Tayyip Erdogan for talks on measures to defeat the militants in Iraq and Syria.
Turkey, a NATO member and Washington's key ally in the region, is reluctant to take part in combat operations against Islamic State militants, or allow a US-led coalition to attack jihadists from its territory.
In this regard, Turkey will continue to share intelligence the United States, give logistical support to Syrian opposition and humanitarian aid to victims of the war in Syria, it added.
"We are important partners, obviously, in NATO, but not just in NATO," Kerry said after meeting with his Turkish counterpart Mevlut Cavusoglu, citing concerns in the Middle East and in Iraq.
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Turkey has been accused of indirectly encouraging the formation of the IS with its wholehearted support of Islamist elements within the Syrian rebellion against President Bashar al-Assad.
On the eve of the visit, a Turkish official told AFP: "Our hands and arms are tied because of the hostages."
The official added that Turkey will "not be involved in any armed operation but will entirely concentrate on humanitarian operations".
A US diplomat said in Ankara: "Obviously there are some sensitivities that Turkey has and we respect that but they are an important counter-terrorism partner.
"That is why we certainly have meetings and engagements with them."
Kerry is due to meet Prime Minister Ahmet Davutoglu later today.