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By Michelle Nichols
UNITED NATIONS, July 28 (Reuters) - Israel and the Palestinians have expressed "serious interest" in a 24-hour truce in the Gaza conflict, but a deal has yet to be reached, U.N. Secretary-General Ban Ki-moon said on Monday, as he raised concerns about the proportionality of Israel's military operation.
Israel eased its Gaza offensive and Palestinian rocket fire from the enclave declined on Monday, as international pressure mounted to end the 21-day conflict in which more than 1,000 people, mostly civilians and predominantly in Gaza, have been killed.
"The people of Gaza have nowhere to run. They are trapped and besieged on a speck of land. Every area is a civilian area," Ban told reporters in New York on Monday after returning from a week in the Middle East trying to help broker a ceasefire.
"The casualty and damage figures also raise serious questions about proportionality," he said.
Under international humanitarian law, proportionality means refraining from launching an attack when it is expected to cause excessive loss of civilian life in relation to the anticipated military advantage.
Following a 12-hour truce on Saturday, Ban called for an additional 24-hour humanitarian ceasefire. His spokesman said in a statement on Monday that the parties had "expressed serious interest in this request but have not yet agreed on the timing."
Ban, who spoke with Israeli Prime Minister Benjamin Netanyahu on Monday, said the temporary pause in fighting during the weekend "revealed how much the massive Israeli assault has devastated the lives of the people of Gaza," where some 1.8 million people live.
"Some described it as a 'man-made hurricane' - whole neighborhoods reduced to debris, rubble; blocks of flattened apartment buildings; scores of bodies still buried under mountains of twisted wreckage," Ban said.
International efforts to secure a long-term ceasefire have so far faltered, with Israel and Hamas presenting almost irreconcilable demands. The Gaza militants want an end to the Israeli-Egyptian blockade of their enclave. Israel said it would ease the siege only if armed groups were stripped of weapons.
"It's a matter of their political will," Ban told reporters of the obstacle to a ceasefire in Gaza. "They have to show their humanity as leaders, both Israeli and Palestinian."
He said it was "morally wrong" for the leaders to allow the deadly violence to continue.
On Sunday, the U.N. Security Council agreed on a statement that backed calls for "an immediate and unconditional humanitarian ceasefire, allowing for the delivery of urgently needed assistance."
The council urged the parties to the conflict to implement a humanitarian truce beyond the Muslim holiday of Eid al-Fitr and to engage in efforts to achieve a durable ceasefire.
The U.N. Refugee Works Agency (UNRWA) in Gaza was sheltering some 173,000 people at its facilities, Ban said.
"Gaza is in critical condition," he said. Ban acknowledged Israel's right to protect itself but warned that "all occupying powers have an international legal obligation to protect the civilians." (Reporting by Michelle Nichols; Editing by W Simon and Jonathan Oatis)