Traffic in the Gaza Strip slowed to a trickle on Monday and some medical centres scaled back treatment as Israeli import cuts hit fuel supplies in the Hamas-run territory.

Many petrol stations in Gaza closed and most private cars and taxis and buses stayed off the streets. Gazans said they were avoiding unnecessary journeys and some were struggling with their daily commutes.

"Who knows when things will be resolved? Who knows -- I may need to take a relative or a neighbour to hospital, so I prefer to stop the engine and preserve what little fuel is in it," said taxi driver Ahmed Khalil.

Israel views Gaza, seized by Hamas Islamists in June, as an "enemy entity" and began restricting the flow of fuel into the territory in October in response to Palestinian rocket attacks. What had been a gradual reduction has intensified, and in the last few days, supplies representing just 15 percent of the coastal strip's daily consumption were being allowed in, said Mahmoud al-Khuzundar, chairman of Gaza's society of petrol company owners.

He said petrol firms considered the amount "good for nothing" and were refusing to accept it in protest over the Israeli blockade.

The Israeli Defence Ministry could not immediately provide figures on how much fuel imports had been cut.

Last week a Defence Ministry official said Israel had only reduced supplies by around 13 percent. Logistical challenges in Israel supplying fuel to Gaza while shunning its Hamas rulers may explain some of the discrepancy, palestinian officials say.

"Yesterday the situation was dark, today it is darker and it gets worse every single hour," Khuzundar said.

Khaled Radi, spokesman for the Hamas-run Health Ministry in Gaza, said fuel shortages had already forced some ambulances off the road and threatened to close clinics, which rely on back-up generators during frequent electricity blackouts.

"The Israeli decision is a death penalty," Radi said. "Our reserve of fuel is almost zero and maybe it will run out by the end of today," he said adding two health centres had already been forced to suspend treatment during power cuts.

Israel's High Court of Justice last week rejected an appeal by human-rights groups to overturn the fuel cuts.

The court found in favor of the Defence Ministry's argument that the fuel supply for vital "humanitarian needs" in Gaza had been maintained.

Khuzundar said Gaza's water supply and sewage system could also be affected if fuel runs out altogether. (Editing by Michael Winfrey)