Oil prices fell on Monday, partly reversing Friday’s rally as investors wait to see if the Israel-Hamas conflict draws in other countries, which could drive up prices and deal a fresh blow to the global economy.

Brent futures LCOc1 slid 34 cents, or 0.4%, to $90.55 per barrel and US West Texas Intermediate (WTI) crude CLc1 dropped 41 cents, or 0.5%, to $87.28 a barrel by 0048 GMT.

Both benchmarks rose nearly 6% on Friday, posting their highest daily percentage gains since April, as investors priced in the possibility of a wider Middle East conflict.

For the week, Brent recorded a gain of 7.5% while WTI climbed 5.9%.

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, president of NS Trading, a unit of Nissan Securities.

“The impact that may involve oil-producing countries has been factored into the prices to some extent, but if an actual ground invasion were to occur and have an impact on oil supply, the prices could easily exceed $100 a barrel,” he said.