By Kenny Katombe
LUBUMBASHI, Democratic Republic of Congo (Reuters) - Police in Democratic Republic of Congo fired tear gas on Wednesday at thousands of supporters of Moise Katumbi, a leading opposition candidate for president who is being questioned over government allegations of hiring mercenaries.
Katumbi is a favourite in the race to succeed President Joseph Kabila who must step down after elections in November and his supporters say the accusations, which could lead to jail, are aimed at derailing his campaign.
The popular former governor of Congo's copper-mining region is accused of hiring mercenaries, including former U.S. soldiers, in a plot against the republic.
Police arrested at least 10 people outside the prosecutor general's office in Congo's second city of Lubumbashi who surged towards the building when Katumbi arrived at about 11 a.m. local time (0900 GMT) for a second day of questioning, witnesses said.
The government denies the allegations against Katumbi are politically motivated. Kabila's opponents accuse him of trying to delay the presidential election to hold onto power beyond the two five-year terms allowed by the constitution.
Dozens were killed in January 2015 in protests over a proposed revision of the electoral law that critics said was a ploy to keep Kabila in power beyond the end of his mandate.
(Writing by Aaron Ross; Editing by Matthew Mpoke Bigg and Louise Ireland)