Kurdish-held areas rocked by blasts

Three bombs that went off in oil-rich Kirkuk are believed to have been directed at Iraqi Kurdish forces based nearby.

SOUNDBITE: EYEWITNESS SAYING:

"Suddenly, right in front of us was an explosion. It happened between several cars. And then we started removing bodies. And then the ambulances came and then we heard ANOTHER explosion. But thank God nothing happened to us. And then more ambulances came and carried off at least a dozen people."

Eighteen people were killed.

Two car bombs went off in this area in the southern part of the city, a third bomb targeted another Peshmerga facility in the northern part of Kirkuk.

It wasn't the only attack on Kurdish forces on Saturday -- an explosion rocked Arbil, the Kurdish capital in the early hours of the morning. Peshmerga forces, which have held steady as Islamic State militants advanced into Iraq, are now battling for control of the country's crown jewel --- oil-rich Kirkuk.

Militants have literally plante