An Israeli airstrike along Gaza's southern border with Egypt killed a Palestinian militant as he prepared to fire a rocket into Israel Sunday.

Sunday's attack came just hours after Islamic Jihad and other radical Palestinian groups in Gaza had announced they would accept an Egyptian-mediated truce to end days of deadly violence – as long as Israel reciprocated.

Then, just before nightfall, Gaza militants fired another rocket into southern Israel. From New York, U.N. chief Ban Ki-moon condemned the rocket incident and urged “maximum Israeli restraint.” European Union foreign policy chief Catherine Ashton also called for calm, saying she “wholeheartedly condemns the indiscriminate targeting of civilians, wherever they are.”

Earlier Sunday, Gaza militants fired about 10 rockets into southern Israel, and Israeli aircraft responded with attacks on several militant sites. Israel closed schools within 40 kilometers of Gaza as a precaution.

On Saturday, Israel's airstrikes killed nine Islamic Jihad members in Gaza – one of the deadliest incidents in and around the Palestinian territory in months. The militant group fired about 20 rockets into southern Israel Saturday, killing one Israeli civilian.

Hamas, which has ruled Gaza since 2007, has avoided direct involvement in the latest round of fighting, but Hamas officials have not criticized their more radical rivals for attacking Israel.

Israel says it holds Hamas responsible for all attacks from Gaza. Islamic Jihad, backed by Iran, is considered more extreme than Hamas.

Prime Minister Benjamin Netanyahu said Israel is not seeking an escalation but will defend itself against anyone who tries to attack the Jewish state.