Uganda police said on Thursday they had detained a legislator and senior official of the country's biggest opposition party for his alleged role in election-related violence in which at least seven people were killed. 

The lawmaker, Muwanga Kivumbi, is vice president of the opposition National Unity Platform party headed by pop star-turned-politician, Bobi Wine, who has been in hiding since last week.

Wine, whose legal name is Robert Kyagulanyi, said he fled a military raid on his house hours before veteran President Yoweri Museveni was declared the landslide winner of the January 15 presidential election.

Police confirmed Kivumbi's arrest in a post on the X platform and said he would "be arraigned before court in due course."

"His arrest is in connection with recent incidents of political violence," police said.

Police and Kivumbi have shared differing accounts of the clashes between security forces and the MP's supporters that erupted overnight after the vote on January 15.

Police said machete-wielding opposition "goons" organised by Kivumbi attacked a police station and vote-tallying centre.

Kivumbi told Reuters that people were killed inside his house, where they were waiting for election results for his parliamentary seat to be announced. He said 10 people had been killed and described it as a "massacre". 

NUP Secretary General David Rubongoya told Reuters on Thursday that he was still gathering information on Kivumbi's arrest and would comment later. 

Hundreds of NUP supporters and officials have been detained before and after the election in what the opposition says has been a campaign to intimidate them. Some have been tortured, they said. 

In an interview with Reuters on Wednesday, Wine said "nobody is safe in Uganda".

"We don't believe in violence, but we believe that when we fight back morally and expose this impunity, maybe it will stop," he said, urging the African Union to speak up against what he alleged as widespread fraud in the election, including claims of ballot stuffing and kidnapping of his agents and supporters.

Museveni's win means that Africa's third longest-ruling head of state will have served for 45 years when the next term ends in 2031. 

He is widely believed to be preparing his son Muhoozi Kainerugaba who is head of the military to take over power when he retires.