Gaza truce talks have shown little outward sign of progress, with Israel seeking guarantees Hamas will be prevented from rearming and the Islamist group demanding Israel first pull out and reopen border crossings.

Egyptian officials have sought to mediate between the two sides, which refuse to talk to each other directly. A Hamas delegation is now in Cairo. Israel planned to send senior defense official Amos Gilad on Monday.

Based on interviews with diplomatic and political sources, here are the main issues being discussed in the talks:

ANTI-SMUGGLING MEASURES

Given opposition from Egypt and Hamas to stationing armed foreign troops along the Gaza-Egyptian border, discussions with Israel have shifted to providing "international support" to Egyptian forces to prevent Palestinian militants from using smuggling tunnels to rearm, diplomats said.

Israeli and European officials said international support for the Egyptians could come in the form of foreign advisers, engineering and border security experts and anti-smuggling equipment, including advanced sonar that can detect tunnels.

In addition to new security measures along the 14.5-km (9 -mile) long Gaza-Egyptian border, known as the Philadephi corridor, Israel wants Western powers to provide assistance to Egypt so it can interdict shipments of arms on land, air and sea before they enter the border area.

Visiting German Foreign Minister Frank-Walter Steinmeier has offered to send specialists next week to Egypt to discuss ways to improve border security to stop the smuggling of rockets and other military equipment to Hamas.

Egypt has offered to deploy more border guards, including elite special forces, along the Gaza border, Israeli officials said. But Israel has raised objections because this would mean reopening the 1979 peace treaty between the two countries.

Israeli aircraft have dropped bunker-buster bombs along the narrow Philadelphi corridor, and large numbers of nearby Palestinian homes have been destroyed. Israel says entry shafts have been built under many border homes.

In the absence of an agreement between Israel and Egypt to halt Hamas smuggling, Israel may opt to recapture the corridor in its entirety, diplomats said.

BORDER CROSSINGS

This is the most important issue for the Palestinians. The negotiations center on reopening Rafah, Gaza's only crossing with Egypt, under the auspices of Palestinian President Mahmoud Abbas's security forces and European monitors.

Rafah has been largely closed since Hamas routed Abbas's secular Fatah forces and took full control of Gaza in June 2007.

Reopening Rafah to passengers and some limited humanitarian supplies would give Abbas a foothold in Gaza. It would also meet a longstanding Hamas demand, though the group could object to being denied any role in border operations.

Abbas, the European Union and the United Nations want Gaza's main crossings with Israel to be reopened to humanitarian goods.

Abbas has sought to retake control of the Palestinian side of the crossings. But it is unclear how much power Israel would be prepared to cede to Abbas or groups like the United Nations.

CESSATION OF HOSTILITIES

If and when a deal with Egypt is reached, Israel would unilaterally end its military operation. Before stopping, it may opt to widen its ground offensive.

Israel will not enter into any formal ceasefire with Hamas because, it believes, doing so would only bolster the group.

Egypt and other Arab states would mediate with Hamas, seeking its commitment to stop firing rockets.

Hamas's leader in exile, Khaled Meshaal, said it would consider a truce only after Israel pulled out all its troops and opened the coastal enclave's border crossings.