* Oil prices surged nearly 6% on Friday

* Israel vows to demolish Hamas, prepares move on Gaza

* US Secretary of State Blinken heads to Israel on Monday

LONDON, Oct 16 (Reuters) - Brent oil futures steadied above $90 a barrel on Monday after topping that level on Friday, as investors waited to see if the Israel-Hamas conflict escalates further.

Brent futures were down 4 cents, or 0.04%, at $90.85 a barrel at 1120 GMT. U.S. West Texas Intermediate (WTI) crude rose by 12 cents, or 0.14%, to $87.81 a barrel.

Both benchmarks climbed nearly 6% on Friday, taking Brent 7.5% higher on the week and WTI up 5.9%.

The war between Islamist group Hamas and Israel poses one of the most significant geopolitical risks to oil markets since Russia's invasion of Ukraine last year, analysts say.

Israeli air strikes on Gaza intensified on Monday, after diplomatic efforts to arrange a ceasefire in southern Gaza to allow foreign passport holders to leave and aid to be brought into the Palestinian enclave failed.

With fears of the conflict escalating, U.S. Secretary of State Antony Blinken will return to Israel on Monday to talk "about the way forward."

"Investors are trying to figure out the impact of the conflict while a large-scale ground assault has not begun after the 24-hour deadline that Israel first notified residents of the northern half of Gaza to flee to the south," said Hiroyuki Kikukawa of NS Trading.

Elsewhere, the United States last week imposed the first sanctions on owners of tankers carrying Russian oil priced above the G7's price cap of $60 a barrel, an effort to close loopholes in the mechanism designed to deprive Moscow of revenue for its energy sales.

"The sudden decision on tightening up of sanctions on ship owners carrying Russian crude over the $60/barrel limit by the US started to niggle and so did the Russian/Saudi meeting concluded by President Putin stating that OPEC+ were achieving 'stability'," PVM analyst John Evans said on price rises at the end of last week.

Russian Deputy Prime Minister Alexander Novak echoed Putin's sentiment on Monday, saying Russia believes it is important to keep working in OPEC+ to stabilize the market. (Reporting by Robert Harvey in London, Yuka Obayashi in Tokyo and Emily Chow; Editing by Susan Fenton and David Evans)