Operation Hammer () was a cross-border operation by the Turkish Armed Forces into northern Iraq between 12 May and 7 July 1997 against the Kurdistan Workers' Party (PKK). The operations objectives were to destroy PKK units in Northern Iraq, to strengthen Massoud Barzani's Kurdistan Democratic Party in its ongoing Civil War with Jalal Talabani's Patriotic Union of Kurdistan in the hole that the KDP would prevent further PKK raids into Turkey, and to counter Iranian influence in the region as Turkey accused Iran of supporting the PKK, and over 2,000 Iranian forces had entered Iraqi Kurdistan that year to aid the PUK.