Mohammad Nabi has stepped down as captain of the Afghanistan national side, after a little more than two years in the job, citing the team's recent performances and his own lack of form.

Nabi tweeted news of his resignation and shared the letter he had sent to the Afghanistan Cricket Board on the social media website.

"I have served Afghanistan's national cricket team as a captain for more than two years," Nabi said in a statement. "I tried my very best to bring victories to our team and nation. I am proud that the national team played the 2015 World Cup under my captaincy.

"Given the recent performance of the team, and particularly my out of form status (sic), I would like to request you to accept my resignation as a captain and allow me to continue to play as a team player.

"I will sincerely provide and share my captaincy experience with the new captain. At the end, I would like to thank ACB, my colleagues and fans inside and outside Afghanistan who supported me all the time."

Nabi was appointed captain after Nawroz Mangal's sacking from the job in March 2013. He had taken over from Mangal in his first stint as captain, too, in 2010.

Under his captaincy, Afghanistan finished second in the World Cricket League Championship in October 2013 to seal a place in their maiden World Cup. He also led Afghanistan in their maiden appearance in the 2014 Asia Cup, where they beat Bangladesh by 32 runs for their first win against a Test-playing nation.

In the 2015 World Cup, Nabi managed 90 runs in six innings at an average of 15 and took three wickets with his offspin at an economy-rate of 5.71, as the side finished sixth in Group A, with their only win coming against Scotland.