Southern Gaza blast kills three

Three Palestinian militants have been killed and several injured in an explosion at the Rafah refugee camp in southern Gaza.

The BBC's Alan Johnston in Gaza says it seems Palestinian militants were trying to plant an explosive device when it went off prematurely.

Some witnesses had earlier said the blast was caused by Israeli gunfire.

Israeli troops, backed by tanks and armoured bulldozers, had moved into the area before dawn.

Among the wounded was a Reuters TV cameraman who suffered a shrapnel wound in his hand, witnesses and hospital officials said.

"We went to inspect the area in which the army was operating," one resident, Raouf Ahmed, told Reuters.

"Suddenly an explosion shook the land... Tanks were positioned along the border with Egypt and Apache helicopters were in the sky as well, but I did not see what caused the explosion," he said.

The Israeli army said it had gone into Yibnah refugee camp to uncover weapons smuggling tunnels. No tunnels have so far been found during this operation.

The border area around Rafah has been a frequent scene of clashes between Israeli soldiers and Palestinian militants.

Army raids in Rafah in May led to the deaths of more than 60 Palestinians, and bulldozers destroyed many buildings.