ADANA, Turkey 

Turkish security forces on Thursday seized a large cache of arms and ammunition meant for use in attacking police stations, thus averting such attacks, according to a security source.

Last week in the southern Adana province, police arrested 50 suspects during an operation against the YPG/PKK terrorist group, said a security source, who asked not to be named due to restrictions on talking to the media.

The PKK is listed as a terrorist organization by Turkey, the U.S. and the EU.

During the arrests, police learned that a large amount of weapons, ammunition, and explosives had been brought to the region from Syria, with the intention of using them to carry out attacks on police stations during the spring festival, the source added.

A search of a hidden weapons cache turned up five Kalashnikov rifles, 88 magazines, 32 bullets, 17 hand grenades, and 12 hand grenade detonation fuses.

The arrests and seizures take place amid Turkey's counter-terrorist Operation Olive Branch against the YPG/PKK in Afrin, Syria, near Turkey's southern border.

The Nevruz festival is celebrated on March 21 mainly in Iran, Afghanistan, India, and Turkic republics such as Azerbaijan, countries of the Caucasus, Albania, and Macedonia.

The festival -- considered to herald spring -- is a UN-recognized international cultural day.

Reporting by Yusuf Koyun:Writing by Sena Guler