Israel said it launched air strikes on two Hamas outposts in the Gaza Strip on Monday in retaliation for rocket attacks on the Jewish state.
The air strikes were mounted on the eve of an Israeli election in which security is a major issue.
Palestinians said at least one Israeli missile hit a building used by Hamas police. There were no reports of any casualties.
The Israeli military said the air strikes were in response to two rockets fired at southern Israel from the Hamas-run Palestinian coastal enclave on Sunday. The rockets caused damage but there were no casualties.
A fragile ceasefire has been in place since Israel ended a 22-day military offensive in Gaza on Jan 18 that was designed to punish the Islamist Hamas group for cross-border rocket and mortar bomb attacks.
Egypt is trying to secure a lasting ceasefire between Israel and Hamas. Diplomats said the Egyptian proposal includes a prisoner exchange and the initial opening of at least two of the enclave's border crossings.
With his opinion poll lead narrowing ahead of Tuesday's parliamentary election, right-winger Benjamin Netanyahu has stressed Israelis' fears of Arab attacks and said government plans to trade land for peace were doomed to failure.
His main opponent, the centrist Kadima party leader Tzipi Livni, said she would continue the US-sponsored peace process with the Palestinians that she pursued as foreign minister -- an outcome favoured by the new Obama administration in Washington.