KAMPALA (Reuters) - Grenades were thrown overnight at the homes of two Ugandan legislators opposed to scrapping the presidential age limit and thereby extending President Yoweri Museveni s more than 31 years in power. One of the legislators, Robert Kyagulanyi, was later arrested by police, his aide said. Kyagulanyi and fellow legislator Allan have been outspoken in efforts to resist an ongoing effort to change the constitution to allow Museveni to seek another term in elections set for 2021.  Museveni has been president since January 1986. Two grenades were thrown at Ssewanyana s residence and three others at Kyagulanyi s. Both legislators were among MPs forcefully ejected from the parliament chamber last week by Uganda s special forces.  The grenades were thrown,  police spokesman Asan Kasingye told Reuters early Tuesday. He said police were investigating, but dismissed as  absurd  the idea that the attacks were politically motivated. Talking to local NBS TV, Ssewanyana said he was scared but would not give up the fight against the constitutional change.  I can t give up and am calling upon all Ugandans not to give up because this is a serious fight. What shows the seriousness is the attacks that they have now started against us ... Attacks involving weapons,  he said.  Police later arrested Kyagulanyi as he left his home on the outskirts of the capital Kampala, his personal assistant, Hakim Katongole, told Reuters.  Kyagulanyi, a top Ugandan musician with a stage name Bobi Wine, joined politics after winning a parliamentary seat in a repeat election in June.  Another police spokesman told Reuters the legislator was arrested for a range of alleged offences including malicious damage, assault of officers on duty, causing bodily harm and others committed during the House brawl. During the fighting, microphone stands were plucked and used as crude weapons, chairs were thrown and bench seats were damaged. The fighting in the chamber pitted legislators opposed to extending Museveni s rule against special forces and legislators favoring the extension. At least five MPs were hospitalized for injuries sustained as they were dragged out of the chamber by plain-clothes security guards that opposition MPs said were special forces soldiers. 