By Patrick Nduwimana
BUJUMBURA, Feb 14 (Reuters) - Burundi's President Pierre Nkurunziza on Friday appointed a deputy to his power-sharing cabinet, angering rivals who said the move was part of a plan to change the law and allow him to remain in power beyond the maximum two terms.
The East African country, which has a complex power-sharing system between the majority Hutus and other minority groups, is facing one of its worst political crises since a 12-year civil war ended in 2005.
Three ministers from the minority coalition partner UPRONA quit the government last week after the president, whose majority party CNDD-FDD is led by ethnic Hutus, sacked his Tutsi vice president, from UPRONA.
The appointment of Prosper Bazombanza from UPRONA has further incensed some elements of his party who oppose his selection to the post. Critics say the president appointed Bazombanza because the vice president backs his bid to change the constitution.
All but one of UPRONA's 17 members of parliament boycotted a vote in the assembly to endorse Bazombanza's nomination. The CNDD-FDD party has 81 legislators in the 106-seat parliament.
"We do not recognise this new deputy president because he was not sent by the leadership of our party," said UPRONA chairman Charles Nditije.
While the departure of the ministers posed no immediate threat to the government, it raised fears of greater ethnic tension in a country reeling from more than a decade of war in a region already grappling with violence in eastern Democratic Republic of Congo, South Sudan and the Central African Republic.
Presidential and parliamentary elections are due in 2015.
Opponents say the proposed constitutional amendments would allow the president to stand for a third term and abolish a requirement which limits Hutus to 60 percent of posts in the government and parliament and guarantees Tutsis the rest.
Tutsis make up about 15 percent of the population of 10 million.
Willy Nyamitwe, deputy spokesman for Nkurunziza, said the president "wanted to avoid an institutional vacuum that some UPRONA leaders want to create" by appointing a deputy. (Editing by Drazen Jorgic; Editing by Janet Lawrence)