British Prime Minister Keir Starmer signed a deal on Monday in which Turkey bought 20 Eurofighter Typhoon jets for 8 billion pounds ($10.7 billion), his office said, deepening the NATO allies’ defence ties and bolstering Turkish air defences.

In July, Turkey and Britain had signed a preliminary purchase deal for 40 Typhoons approved by Eurofighter consortium members including Germany, Italy and Spain, represented by Airbus AIR.PA, BAE Systems BAES.L and Leonardo LDOF.MI.

Starmer met President Tayyip Erdogan in Ankara on Monday to sign the agreement, which comes as Turkey seeks to leverage the advanced warplanes to make up ground with regional rivals such as Israel, which has unleashed strikes across the Middle East this year.

Turkey, enjoying its warmest ties with the West in years, has sought to procure the Eurofighters and also potentially U.S.-made F-35s to backstop its ageing fleet of mostly F-16s.

TURKEY HAS NATO’S SECOND BIGGEST MILITARY

Europe has increasingly turned to Turkey, NATO’s second-largest military and a major exporter of armed drones, to reinforce its eastern flank and potentially backstop any future post-war stabilisation force in Ukraine.

Last week, citing a person familiar with the matter,Reuters reported that Turkey was nearing a deal in which it would promptly receive 12 Typhoons, albeit used, from previous buyers Qatar and Oman to meet its immediate needs, with more new jets coming from Britain in future years.

Last week, Erdogan visited Qatar and Oman in part to discuss the plan.

Turkey, which wants to fill a gap before its own KAAN fighters are ready in coming years, opened talks on obtaining the Typhoons in 2023. Last year Ankara secured a $7-billion deal with Washington for 40 F-16s that have faced delays.

Air attacks by Israel – the region’s most advanced military power with hundreds of US-supplied F-15, F-16 and F-35 fighters – on Turkey’s neighbours Iran and Syria, as well as on Lebanon and Qatar, have unnerved Ankara over the past year and persuaded it to revamp its defences, officials said.

The visit marked Starmer’s first to Turkey since taking office last year.