Several thousand Turkish troops crossed into northern Iraq early Wednesday to chase Kurdish guerrillas who operate from bases there, Turkish security officials told The Associated Press. Two senior security officials... said the raid was limited in scope and that it did not constitute the kind of large incursion that Turkish leaders have been discussing in recent weeks... The officials did not say where the Turkish force was operating in northern Iraq, nor did he say how long they would be there. The officials said any confrontation with Iraqi Kurdish groups, who have warned against a Turkish incursion, could trigger a larger cross- border operation. The Turkish military has asked the government in Ankara to approve such an incursion, but the government has not given formal approval.