The warplanes targeted a training ground west of Beit Lahiya on Monday that was used by the militant wing of the Hamas movement ruling Gaza, security forces and witnesses said.

While no damage or casualties were caused, Hamas said in a statement that the raid - the first air strike on Gaza since August 14 - was "an escalation which aims to terrorise … our people."

It came after Gaza militants launched two missiles at the southern Israeli city of Ashkelon, an army spokeswoman in Tel Aviv said. Again, there were no casualties.

The flare-up along the border is not tipped to delay Israel's release of the prisoners, which was agreed on Monday. Granting the 26 prisoners freedom is part of the ongoing peace talks between Israel and Palestine, but has attracted criticism.

All were convicted for killing Israeli nationals, according to details published by Israel's prison service. Relatives of those murdered were given 24 hours to appeal the decision to free the prisoners.

"Until I received the call I had hoped that I wouldn't be part of this round (of releases). This is a great blow for us," said Ayelet Osher, whose husband was stabbed to death by one of the prisoners in 1991.

Peace talks in mind

Israel's Prime Minister, Benjamin Netanyahu, has pledged to free 104 Palestinian prisoners in four stages, with Tuesday's release the second round. The move is part of the commitments that led to the resumption on July 30 of peace talks brokered by the United States.

Right-wing members of Netanyahu's government have accused him of freeing "terrorists," while his supporters say he would have been forced to freeze controversial resettlement construction in the West Bank and East Jerusalem if he had not followed through on the release.

ph/rc (dpa, AFP)