Powell: No decision has been taken on Iraqi targets
Mr Powell is thought to have been pressed by Turkish leaders on whether Iraqi President Saddam Hussein might be targeted.
But Mr Powell told a news conference in Ankara that Afghanistan remained the only current US target.
"The president has made no decision with respect to what the next phase in our campaign against terrorism might be," he said, "nor has he received any recommendations yet from his advisers as to what he might do next."
Mr Powell also made reference to Turkey's internal conflict with the militant Kurdish separatist group, the PKK, saying that, as Turkey had suffered from terrorism, it recognised the importance of the US mission.
The BBC's Tabitha Morgan in Ankara says his comments on the PKK are bound to be well received by the authorities there.
Mr Powell is on a 24-hour visit officially to thank Turkey - the only Islamic country in Nato - for its offer to deploy troops in the war against Afghanistan.
But Turkey fears that any attack on Iraq could create a political vacuum there, creating knock-on effects for Kurdish areas of Turkey.
Public disquiet
Officials believe the removal of Saddam Hussein could lead to an independent Kurdish state inside Iraq, encouraging Kurdish separatists inside Turkey to seek to follow suit.
The Turkish public are also thought to be wary of military action.
"Maybe they want to use Turkey's influence on northern Iraq and the Iraqi people. It will not be good for Turkey."
Another resident said: "We don't want anything to happen around us. As it's close, we will have some difficulties and problems and we are not in a mood to cope with that because we are in an economic crisis. We just want stability."
But Tabitha Morgan says that, whatever the public mood, recent signs are that Turkey could be softening its position on US policy towards Iraq.
The country's defence minister said earlier this week that changing circumstances might, as he put it, bring new evaluations on to the agenda.
Turkey will also want to maintain a strong negotiating position with the US.
Rapid reaction force
Mr Powell's talks with Turkish leaders are also expected to refer to a possible compromise deal over the use of Nato resources by Europe's planned rapid reaction force.
It is thought that Turkey has provisionally accepted a deal allowing the force to use Nato bases in Turkey, although details have not been made public.
Cyprus is also expected to feature - on the day that Turkish Cypriot leader Rauf Denktash hosts a dinner for Cyprus President Glafcos Clerides.
The two Cypriots agreed at face-to-face talks on Tuesday to resume full negotiations on the divided island in January, and to continue talking until the issue has been resolved.