Israel said on Wednesday it has agreed to the principles outlined by Egypt for a ceasefire in the Gaza Strip but that the two have yet to iron out key details about how it would be implemented.

Senior Israeli defence official Amos Gilad will travel to Cairo on Thursday to discuss the issues, officials said.

Israel has hinged halting its military offensive in the Hamas-ruled Gaza Strip on international and regional commitments to prevent the Islamist group from replenishing its stockpiles of rockets capable of hitting deep inside the Jewish state.

The Egyptian proposal calls for increasing border security to stop the smuggling, but it offers few specifics beyond that.

"There is a broad understanding on the general principles of a solution," said Mark Regev, spokesman for Israeli Prime Minister Ehud Olmert.

But a senior Israeli official, speaking on condition of anonymity, cautioned: "Translating those principles into practical action is a challenge that is still ahead of us".

Western and Israeli diplomats said negotiations centred on the idea of sending specialised international forces or teams, equipped to search out and destroy smuggling tunnels, to the so-called Philadelphi corridor that runs between Gaza and Egypt.

In addition, Israel and Western powers are discussing a naval contingent to prevent smuggling by sea.

International Middle East envoy Tony Blair said he thought the elements of a ceasefire plan had been broadly agreed but that the details now had to be worked out and that both sides were waiting to see the small print.

European Union foreign policy chief Javier Solana likewise said the elements of a ceasefire deal were coming together.

But getting Israel, Egypt and Western powers to agree on the means of implementation may prove difficult.

The Netherlands and Denmark have proposed that the EU contribute to "watertight control and monitoring of the Egyptian-Gaza border".

But Solana said hunting for tunnels would "be done probably with technology, not with people".

Israeli officials say advanced sonar can detect some tunnels but they were sceptical technology alone would prevent Palestinians from rebuilding secret passages under the sandy, 14 km (9 mile)-long Philadelphi corridor.