Militants in the Gaza Strip fired a projectile that hit an open field in southern Israel on Wednesday causing no damage or casualties, police told AFP.
Spokeswoman Luba Samri said it struck in the Eshkol region. A military spokeswoman could not say whether the projectile was a mortar shell or rocket.
No group immediately claimed responsibility for firing the projectile.
Palestinians in the West Bank and Gaza were marking on Wednesday what to them is the Nakba -- Arabic for “catastrophe” -- of the creation of the Jewish state in 1948 and exodus of 760,000 Palestinians from their homes at that time.
Thousands of Palestinians were marching in Hamas-ruled Gaza to mark the Nakba, bearing signs calling for “the return to the Palestinian villages and towns”.
Over the past two months, there has been an uptick in rocket fire on southern Israel after more than three months of complete quiet following a deadly confrontation in November which ended with an Egyptian-brokered truce.