Dubai's Sidara said on Monday it was walking away from its plan to buy UK's John Wood Group WG.L, citing rising geopolitical risks and uncertainty in the financial market, prompting the British engineering group's shares to plunge 40%.

Wood had rejected Sidara's previous four buyout attempts, citing valuation concerns. The Dubai-based engineering and consulting firm had until this Friday to make a firm offer or walk away for at least six months.

There are growing concerns that the 10-month war in Gaza between Israel and Hamas could spread in the Middle East, a key growth area for Wood's strategy.

Wood, which provides consultation, management of assets and engineering services for the energy and materials sector, operates in more than 60 countries with the Middle East and Africa contributing about 18% of its total revenue, according to the group's 2023 annual report.

Wood said on Monday it was confident in its strategic directions and affirmed forecasts for 2024 and next year with expectations for core earnings growth to exceed its medium-term target and significant free cash flow in 2025.

Sidara had previously approached Scotland-based Wood Group with proposals ranging from 205 pence to 230 pence per share with the latest offer valuing Wood Group at about 1.56 billion pounds ($1.99 billion) which it had said would be it final offer.

Sidara had received a deadline extension twice over June and July to make a final offer for Wood Group.

Sidara is the second suitor to walk away from Wood in the past 15 months after U.S.- based Apollo Global Management APO.N abandoned its 1.7-billion-pound bid for the UK-listed company following five approaches that Wood rejected.

Activist shareholder Sparta Capital Management has been pushing Wood Group to consider either selling itself or reconsider its UK listing.

Wood Group shares have lost more than 87% since their all-time high of 927 pence hit in August 2013.

($1 = 0.7822 pounds)

(Reporting by Prerna Bedi and Shanima A in Bengaluru; Editing by Varun H K and Emelia Sithole-Matarise)