Virat Kohli shocked the Indian cricket world on Saturday by abruptly resigning as the national side's Test captain, after leading the team to memorable overseas victories in his seven years in charge.

The 33-year-old, considered one of the best batsmen of his era, took to Twitter to announce his decision a day after India's 2-1 series defeat in South Africa.

“It's been seven years of hard work, toil and relentless perseverance everyday to take the team in the right direction. I've done the job with absolute honesty and left nothing out there,” Kohli said in his statement.

“Everything has [to] come to a halt at some stage and for me as Test captain of India, it's now. There have been many ups and also some downs along the journey, but never has there been a lack of effort or lack of belief.”

After Kohli's announcement of relinquishing the Test captaincy, the Indian cricket board tweeted: "BCCI (Board of Control for Cricket in India) congratulates team India captain Virat Kohli for his admirable leadership qualities that took the Test team to unprecedented heights."

The board's secretary Jay Shah wrote on Twitter after Kohli's surprise announcement: “Virat turned the team into a ruthless fit unit that performed admirably both in India and away. The Test wins in Australia and England have been special.”

The feisty top order batsman has had a difficult relationship with the BCCI since stepping down as the Twenty20 captain after last year's World Cup.

Read: 5 things that went wrong for India at the T20 World Cup

That cost him the One-Day International captaincy as well, with the BCCI installing Rohit Sharma as captain in both the short formats.

Kohli, who took over the reins in 2014, led India in a record 68 test matches, winning 40 and losing 17.

BCCI officials were not immediately available to confirm who would take over as India's next Test captain, although opener KL Rahul's name has already started doing the rounds.