The latest round of talks between Egypt and Hamas has ended in Cairo without a final agreement on a truce in Gaza.

Egyptian officials had expressed hopes a deal would be signed on Thursday, but Hamas negotiators returned to Gaza and Damascus overnight with a number of issues still unresolved.

Despite the setback, Hamas delegates are expected to return to Egypt on Saturday and officially accept an at least 12-month truce with Israel.

Mohammed Nasr, a member of the Hamas delegation that travelled to Cairo, told Al Jazeera that some of the proposals discussed were "ambiguous".

"Our brothers in Egypt, they need some time to contact the other side [Israel] in order to get clarifications and answers to our questions and issues raised by the [Hamas] movement," he said.

Both sides declared separate ceasefires in January after three weeks of an Israel assault in Gaza that left more than 1,000 Palestinians dead.

Some rockets have been towards Israel since then, and the Israeli military has carried out regular air raids in the territory.

Sticking points

One of the key sticking points in reaching agreement is the opening of Gaza's borders.

Hamas and other Palestinian groups have demanded Israel lifts its blockade of the Gaza Strip, which prevents even humanitarian aid from coming in.

Israel, however, has cited concerns of weapons smuggling into the territory and says it wants to keep at least a quarter of the border crossings closed as leverage until Hamas releases Gilad Shalit, an Israeli soldier captured in 2006.

Hamas has so far refused to link the two issues, saying Shalit will only be released if Israel frees some of its held members in exchange.

Another sticking point is the length of the ceasefire agreement.

Israel has asked for a 18-month truce, while Hamas has called for a year-long truce.

Salah al-Bardawil, another member the Hamas negotiating team, told Al Jazeera that while there are still several unresolved issues, he was confident that a deal would be reached within days.

Furthermore, he said Egypt has pledged to host all the Palestinian factions, including Hamas, at a conference on February 22 to deal with such issues as national unity, security and political prisoners.