Palestinian witnesses say a 14-year-old Palestinian boy was killed and at least two others were wounded when Israeli forces raided the Rafah refugee camp in the southern Gaza Strip, Thursday morning.

They say the boy was hit when Israeli forces opened fire near a school.

The Israeli military says there was a heavy exchange of gunfire as soldiers faced fierce resistance from Palestinian gunmen while searching for weapons smuggling tunnels in the area near the Egyptian border.

The raid came a day after three members of the Palestinian militant group Hamas were killed in an Israeli air strike south of Gaza City.

The Israeli military says the helicopter targeted the men because they had carried out attacks on Israel and were planning more attacks.

Hamas says the three were on their way to launch an attack and vowed revenge.

Israel has used air strikes to kill dozens of people allegedly linked to Palestinian groups that have carried out suicide bombings against Israelis.

In a separate incident, one Palestinian militant was killed when his house blew up in the Rafah refugee camp. Israeli military says the man was killed when a bomb he was making exploded prematurely.