JERUSALEM (Xinhua) -- Israel struck a military post in the northern Gaza Strip overnight between Sunday and Monday after Palestinian militants launched explosive balloons from the enclave into Israel, Israeli army said.

The army said in a statement that "an IDF (Israel Defense Forces) aircraft struck an observation post" belonging to Hamas, an Islamist Palestinian movement that runs Gaza.

The strike was a response to explosive balloons that had been launched during Sunday at southern Israel and sparked fires.

Israel and Hamas had fought three rounds of war with occasional bursts of violence between them.

Over the past months, both sides kept an unofficial ceasefire.

Gaza Strip has been under Israeli and Egyptian blockade since 2007. Enditem