UPDATE 1-Adidas extends World Cup soccer sponsorship until 2030
* Deal covers Russia 2018 and Qatar 2022
* Adidas has been official partner since 1970
* Battles Nike for soccer market leadership
FRANKFURT, Nov 21 (Reuters) - 45German sportswear maker Adidas will remain the official partner and sponsor of the FIFA World Cup until 2030 as it defends its market leadership in soccer against U.S rival Nike.
Under a deal covering the four tournaments from 2018, Adidas will provide the match balls and the uniforms of volunteers who help fans find their way around. It will also sell licensed World Cup products and have its name on advertising at venues.
"Adidas is an integral part of the FIFA World Cup story, quite literally featuring at the heart of the action at every tournament since the 1970 World Cup," FIFA Marketing Director Thierry Weil said in a statement on Thursday.
The last contract extension with FIFA was announced in 2005, covering the 2010 World Cup and next year's tournament in Brazil. That deal was estimated to be worth $350 million. Adidas declined to give financial details of the latest extension.
Adidas and Nike are almost neck and neck in the market for soccer kit - replica shirts, balls and boots - estimated to be worth around 5 billion euros ($6.7 billion) annually.
While Adidas was boosted by last year's Olympics and European soccer championships, it has struggled to maintain momentum in 2013, losing ground in the European market for sports apparel to the larger Nike and warning of smaller than expected growth in profits.
But all eyes are already on Brazil. Adidas has forecast record soccer sales of more than 2 billion euros in 2014, a jump from the 1.5 billion it raked in for the last World Cup year.
It has already kicked off its World Cup soccer campaign, launching new lines of boots and the jerseys for teams like Germany, Spain and Argentina in time for them to make their way into the Christmas stockings of fans.
Adidas said sales of World Cup jerseys and boots would start to boost results in the last three months of this year.
"This unique partnership and our extensive presence at all FIFA World Cups will help us to expand Adidas' position as the leading football brand worldwide," Adidas Chief Executive Herbert Hainer said.