Jerusalem  - US President George W Bush and his First Lady Laura opened the second day of a 48-hour visit to Israel Wednesday by touring the ancient fortress of Masada, overlooking the Dead Sea and deserts south-east of Jerusalem.

The fortress was built by the Jewish Roman client king Herod the Great in the first century BC, famous for where a group of Jewish zealots made their last stand against the Romans and committed mass suicide rather than surrender to the Roman legions.

Bush is scheduled to make a key-note address to Israel's Knesset (parliament) later Thursday, on the occasion of the 60th anniversary since the country was established on May 14, 1948.

But his visit and the anniversary celebrations were marred by another flare up in violence in and from the Gaza Strip.

At least 16 Israelis were injured late Wednesday when a rocket fired from northern Gaza penetrated the roof of a shopping mall in the southern Israeli coastal city of Ashkelon, striking a clinic on the top floor. A mother and her toddler daughter were among the wounded, as were some of the medical staff and two pregnant women. Dozens of others were treated for shock.

The strike came after clashes between Israeli troops and local militants in southern and northern Gaza left at least three Palestinian militants and a civilian dead. At least nine other Palestinians were wounded.

Olmert late Wednesday called the rocket strike on the shopping mall "intolerable and unacceptable" and said Israel would "take the necessary steps so that this will stop." (dpa)