* Cement earmarked for three projects, by mid-August
* Israel hosts U.S. national security adviser
By Dan Williams
JERUSALEM, July 29 (Reuters) - Israel will allow some cement into the Gaza Strip for reconstruction, officials said on Wednesday, signalling flexibility on a blockade as Washington intensified efforts to broker peacemaking with the Palestinians.
After Hamas Islamists seized Gaza in 2007, Israel curbed imports that it said could be used to make arms or bunkers. The lack of cement and steel has been especially felt since Israel's December-January offensive, which devastated the coastal strip.
Though the West shuns Hamas, Gaza's deepening privation and isolation have hindered the U.S.-led campaign to revive peace talks between Israel and Palestinian President Mahmoud Abbas, who is locked in a power-struggle with the Islamists.
The announcement that cement would be admitted for three Gazan projects coincided with a visit to Israel by U.S. national security adviser Jim Jones. He follows closely on U.S. Defense Secretary Robert Gates and senior U.S. envoy George Mitchell.
After meeting Israeli Prime Minister Benjamin Netanyahu on Tuesday, Mitchell said he saw "good progress". Netanyahu and President Barack Obama are trying to bridge a rift over Jewish settlements on West Bank land Palestinians want for a state.
One Israeli official said that Defence Minister Ehud Barak gave his approval in principle to the cement imports before this week's influx of American officials, but added: "Shall I say the timing of this publication isn't good? Of course it's good."
The Defence Ministry was working on ways of ensuring that the cement reached only its intended humanitarian projects, rather than Hamas, the official said.
"I believe completion of the process will take another one or two weeks," he said.
Another Israeli official said that one of the projects that would be given cement would be a flour mill in Gaza.
Netanyahu has said there cannot be full peace negotiations with the Palestinians until Abbas defeats Hamas and imposes his authority in Gaza. Israel has been focussing on economic projects in the West Bank, where Abbas still holds sway.
On Tuesday, Netanyahu called on Palestinians in impoverished Gaza to rise up against the Islamists' rule.
Hamas was "not endearing itself to the Palestinians in Gaza," he said in a speech. "Were it possible for them (Palestinians) to cast off the regime they would do so, and I tell you, they will be capable of doing so." (Editing by Jon Boyle) (For blogs and links on Israeli politics and other Israeli and Palestinian news, go to blogs.reuters.com/axismundi)