A senior United Nations official says new border restrictions on Gaza by Egypt and Israel have paralyzed the territory's construction industry and idled 10 percent of the workforce.

Israel and Egypt have imposed restrictions since the Islamic militant Hamas seized Gaza in 2007. In July, Egypt shut down smuggling tunnels under its border with Gaza. Israel barred the import of all construction materials to Gaza last month after it discovered two concrete-lined border tunnels dug by militants.

Robert Turner of the main U.N. aid agency in Gaza on Thursday urged Israel to lift the restrictions that he said put U.N. building projects worth $60 million on hold.

Maj. Guy Inbar, an Israel military official, says Israel first needs assurances the materials won't be diverted to militants.