Sentence:  A curfew was clamped down on December 21 upon the Arab village of Battir, south of Jerusalem, near where security forces on December 20 found the rocket launchers from which two <WSD>Katyushas</WSD> were earlier fired into a Jerusalem residential area. 
Meaning of the word marked with <WSD> tags:  A type of rocket which can be launched from a Katyusha.