Ugandan opposition presidential candidate Bobi Wine was arrested on Tuesday after handing in his nomination papers to the election body, his party's spokesman said.

"They (police) used a hammer and broke the windows of his vehicle and forcefully dragged him out ... they bundled him into their own vehicle and took off," Joel Senyonyi, spokesman for the NUP party, said, adding he did not know why Wine was arrested.

Police spokesman Luke Owoyesigire said he had yet to receive a briefing on the arrest and promised to comment later.

Wine, 38, a musician turned politician whose real name is Robert Kyagulanyi, aims to end Yoweri Museveni's 34 years in power, making him Africa's third longest-ruling president. Elections are scheduled for February next year.

Wine's youthful age and his music have earned him a large following in the relatively young country of 42 million, rattling the ruling National Resistance Movement party and drawing a security crackdown on his supporters.

Since Wine expressed his presidential ambition, police and the military have repeatedly dispersed his rallies, and beaten and detained his supporters. 

In August, the Ugandan court charged Wine with intending to "annoy, alarm or ridicule" the president during a court appearance. He also faces a treason charge for his alleged involvement in an opposition rally last year that saw some protesters stone Museveni's convoy.

Museveni, the presidential candidate of the ruling National Resistance Movement (NRM) party, was cleared to run in the elections, and launched his five-year reelection manifesto for the 2021 general elections on Monday.

Legislators in 2017 voted to remove the age limit of 75, paving way for Museveni, who is now 76 to run for the presidency in the 2021 polls.

According to a previous law in the east African country, people over the age of 75 were not allowed to run for the presidency.

(With input from agencies)