Israel's prime minister has said that no long-term ceasefire will be agreed with Hamas unless an Israeli soldier captured in 2006 is released.
"Israel will not reach any understandings regarding the calm before the release of Gilad Shalit," a statement from the office of Ehud Olmert said on Saturday.
The call for the release of Shalit, who was seized in a cross-border raid by Palestinian fighters, came after Hamas accused Israel of undermining the chances of a long-term truce in the Gaza Strip by changing the conditions of a proposed deal.
"The shelling and escalation has coincided with a backtracking in the Zionist position related to the length of the truce," Fawzi Barhum, a Hamas official, said.
"[Israel] has demanded a long-term, open-ended truce and not an 18-month truce as had been established," he said.
Egyptian mediation
Egypt has been attempting to broker a lasting truce between the two sides since Israel ended its 22-day assault on the Gaza Strip, which left more than 1,300 Palestinians dead.
Israel unilaterally decided to halt the offensive on January 18, before Hamas announced its own ceasefire the following day.
There had been media reports in recent days suggesting that the two sides were close to a deal after Egyptian officials said that a truce could be agreed "in days".
However, Olmert's office on Saturday said Israel "is not conducting any negotiations and will certainly not reach any understandings with Hamas."
"We emphasize that now what stands on top of Israel's priorities are: the security of the citizens of the south of Israel and the release of Gilad Shalit. Israel will exert all efforts to promote these two goals."
Hamas has previously said that negotiations over Shalit's release should take place as part of separate talks on a possible exchange for hundreds of Palestinian prisoners held in Israeli jails.
Crossings demand
Khaled Meshaal, Hamas's exiled political leader, told Libyan television on Thursday that "until now there is no agreement concerning Shalit. Israel is trying to mix up the files and link his fate to the opening of the crossings".
Hamas wants the crossings into the Gaza Strip reopened as part of a truce deal to bring to an end the crippling blockade of the territory that has restricted the delivery of basic supplies, food and fuel.
PHOTO CAPTION
Smoke in Rafah after an Israel air strike targeting tunnels that link the southern Gaza Strip with Egypt on February 13, 2009.
Al-Jazeera