Israel was to blame for Internet and phone services being cut off in Gaza for about 12 hours, Al Jazeera reports.
Palestinian telecommunications officials said Israeli bulldozers cut fibreoptic lines into Gaza on Tuesday, it says.
Israel denied its army had any involvement and said the power blackout was probably an "internal Palestinian problem", AFP reports.
A spokesman for the Israeli army wrote on Twitter that bulldozers had not been digging at Nahal Oz, where the cables cross into Gaza.
Al Jazeera reports:
Officials from PalTel, which operates Internet and phone networks in Gaza, told Al Jazeera that Israeli bulldozers cut the cables at Nahal Oz two weeks ago, forcing the company to use another set of communications lines at the Erez crossing, which were then cut on Tuesday.
PalTel needed permits to repair the lines but had not yet received them from Israel, chief executive officer Ammar al-Aker said.
Almost all attempts to dial into Gaza from abroad, including via the internet, were met with error messages.
Israeli-provided wireless and Blackberry services remained on in some areas, Ma'an News reported.
It comes after Foreign Minister Avigdor Lieberman said on Sunday Israel should sever ties with the Palestinian Authority over its plans to ask the United Nations in September to upgrade the Palestinians' status, Reuters reports.