JERUSALEM, Oct. 28 — Israeli officials said today that Israel had begun reducing fuel supplies to Gaza and had closed down one of the two crossings through which food, medicine and other supplies pass into the strip, in line with a recent government decision to respond with sanctions to continued rocket fire from the Hamas-run territory.

Shlomo Dror, a spokesman for the Coordinator of Activities in the Territories, the Israeli agency that oversees supplies to Gaza, said the plan was to reduce the amount of fuel by 5 to 11 percent. He said that the industrial fuel needed to operate the Gaza power plant would not be affected, but that there would be cuts in the supply of benzene, which is mostly for private use, and diesel, which is mostly used for public transportation and service vehicles.

Mr. Dror said that the Sufa crossing had been closed, leaving the Kerem Shalom crossing in the south as the only point of entry for goods into the strip.

The main commercial crossing on the Gaza-Israel border, Karni, has been closed since the militant Islamic group Hamas took over Gaza in June. Hamas routedthe Fatah forces there, including the elite Presidential Guard that used to secure the Palestinian side of the border crossings, by agreement with Israel. The Rafah crossing on the Gaza-Egypt border has also been formally closed since June.