ISRAEL'S attack on Lebanon should serve as a warning of the risks to the region if no comprehensive settlement were found, the US Secretary of State, Warren Christopher, said yesterday.

He was speaking after talks in Alexandria with President Hosni Mubarak of Egypt at the start of a tour of regional capitals delayed by the Israeli action last week. The tour's original aim was to persuade the parties - Israel, Jordan, Syria and the Palestinians - that the peace process still had life.

'We both agreed that recent events there can serve as a reminder to all parties that the Arab-Israeli negotiations can quickly deteriorate . . . if we do not take this moment for peacemaking,' he said. 'Decision time is rapidly approaching. As a full partner, the United States is prepared to stay the course.'

A declared aim of the operation was to pressure the governments in Beirut and Damascus to rein in the gunmen of Hizbollah in southern Lebanon. The move by the Lebanese government - which may prove difficult to implement on the ground - to deploy troops in areas under Hizbollah control appeared to be a result of the Israeli operation.

Uri Lubrani, an Israeli defence ministry official who for years has been the leading figure dealing with south Lebanon and the Shia question, expressed the hope that Syria's role in arranging the ceasefire would bode well for the peace talks.

'Syria has definitely changed in that it's a partner to such an arrangement as this,' Mr Lubrani said. 'I hope it's not tactical but strategic and the start of a process that will enable us to progress in negotiations with Lebanon towards a permanent agreement.'

However, an ominous warning was issued by the Iranian cleric Ali Akbar Mohtashemi, the former interior minister who helped to set up Hizbollah. He said the organisation should strike at US 'economic, security and espionage centres in Lebanon, the region and other parts of the world' in revenge for Washington's support of Israel.

Meanwhile, in the occupied Gaza Strip a militant of the Palestinian Islamic Jihad killed a tax collector working for the Israeli military government and wounded five security workers yesterday by ramming a school bus commandeered from a UN Relief and Works Agency into two cars, the Israeli army said.