Valtteri Bottas will drive for Mercedes again in the 2020 Formula One season after the team announced they had exercised their option to extend his contract.

The position of the second Silver Arrows seat alongside Lewis Hamilton has been the subject of much debate in recent weeks and months, with the possibility of Max Verstappen teaming up with the defending champion mooted on several occasions.

Esteban Ocon, working with Mercedes after losing his place at Force India, was also a potential option to replace Bottas.

However, the Finn, who sits second in the drivers' standings heading into this weekend's Belgian Grand Prix, will remain Hamilton's team-mate for at least another year.

With his future secured on Thursday, Bottas, who joined Mercedes in 2017, outlined his target to win the drivers' championship next year.

"I am very happy and proud to be part of the team for a fourth season and wish to thank every team member and the board of Mercedes for their trust and belief in me," he said.

"My performances have been getting better and better each year and this is a great way to kickstart the second half of 2019.

"My overall target is to become Formula One world champion. I believe that on paper, and from my experience with the team, Mercedes is the best option for me to achieve that goal in 2020.

"We have nine races to go this season and I am determined to keep improving at every one of them. Now, all my thoughts are on Spa and delivering a strong performance with the team this weekend."

Team boss Toto Wolff added: "For 2019, we set Valtteri the challenge of coming back even stronger than we saw him in the first part of 2018 - and he has achieved that, with some really impressive performances in the early races this year.

"Although it has been his most successful first half of a championship so far, he is hungry for more and determined to keep on improving and raising his level. That's the mindset we want from all our team members.

"The results we have achieved together with Valtteri are no coincidence. He has been an integral part of our championship success in the past two seasons, his teamwork with Lewis has been exemplary and he has shown real strength of character in how he has responded to setbacks.

"I'm delighted that he will stay with the team for another season at least - and look forward to seeing him raise the bar even further."

Bottas joined Mercedes from Williams ahead of the 2017 campaign and celebrated his first three F1 race wins in his debut season with the Silver Arrows, finishing third in the standings.

The 30-year-old appeared to take a backwards step last term, however, failing to register a single win, with team orders favouring Hamilton in his title pursuit when Bottas challenged in Russia.

Any tensions were quickly forgotten at the start of this season as Bottas contributed to Mercedes' outstanding start, winning two of the first four races as Mercedes began with five straight one-twos.

His form faltered before the mid-season break - retiring in Germany and finishing eighth in Hungary - but Bottas remains on course for his best season finish.