Quartet envoy Tony Blair canceled a planned trip to the Gaza Strip on Tuesday after receiving warnings from the Shin Bet (Israel Security Agency) that terrorists planned to target his convoy. Blair also canceled a visit to Sderot. Blair's itinerary was to have included a tour of a Gaza waste water project and meetings with traders and UN officials, but not with leaders of Hamas. Still, the Islamist movement had made security arrangements for the former British prime minister, setting up checkpoints in areas he was expected to tour, banning cars from roads, and lining streets with black-clad policemen carrying AK-47 rifles. Israeli security officials told The Jerusalem Post the threat against Blair was "concrete" and was received early Tuesday morning. Shin Bet officials then contacted Blair's office and relayed the intelligence. Defense Minister Ehud Barak, diplomatic officials said, then called the envoy and detailed the seriousness of the risk. "The level of the threat was explained to Blair, although he was told that if he wanted to go to Gaza Israel would not prevent him," a security official said. A key stop on Blair's trip was to have been a northern Gaza waste water project being built with international funds. The Middle East envoy had not been expected to meet officials from Hamas, which is recognized as a terrorist organization by the US, EU and Israel. Blair said the threat was "specific and credible," forcing him to call off the trip, but that it was a postponement, not a cancellation. He denied that Jerusalem had pressed him to call off the trip. "I intend to go to Gaza as soon as I can, and I will continue to press for help for the people there," he said. "It was a pity, because it would have been important to go and see for myself the situation in Gaza." Taher Nunu, a Hamas government spokesman, denied there were any security threats against Blair. "Gaza is still open for all visitors, to break the siege and see the extent of suffering here," he said. Blair's spokesman, Matthew Doyle, said the envoy called off the visit "due to a specific security threat which would have made it irresponsible to proceed, not just for those visiting but also [for] the local community." "He looks forward to being able to go to Gaza again in the future and will of course in the meantime continue to work to improve the conditions for the people there," Doyle added. Blair has said in recent weeks that a new policy toward Gaza needs to be developed, pointing to the growing suffering of Gazans, but has not offered a plan. "We are very disappointed," said John Ging, Gaza director for UNWRA, which in responsible for Palestinian refugees. Hamas expressed deep disappointment over the cancellation of Blair's visit. The movement's leaders said they had been hoping to use the visit to demonstrate that Gaza was a safe place under Hamas's rule. "We were hoping to show Blair and the world that Hamas has succeeded in imposing law and order in the Gaza Strip," they said. Hamas Prime Minister Ismail Haniyeh said Israel did not want Blair to visit the Gaza Strip "so he won't see the results of the catastrophic siege." Haniyeh said his government had taken all the necessary security measures to protect Blair. "We were prepared to do everything to make the visit successful," he said. "But we were surprised today to hear about the [Israeli] pressure on him to cancel his visit." Haniyeh added that he had hoped to brief Blair on the effects of the blockade on the Gaza Strip so that he would convey his impressions to the members of the Quartet. Hamas spokesman Sami Abu Zuhri said the decision to cancel the visit was also the result of pressure from the Palestinian Authority leadership in Ramallah. "They didn't want Blair to see the improvement in the security situation in the Gaza Strip," he said. "The Palestinian Authority's security forces were responsible for the anarchy and lawlessness here." Also on Tuesday, a Palestinian health official said a Gazan man was killed when Egypt blew up a tunnel used to smuggle contraband into the Strip from Sinai. AP contributed to this report.