A court in Comoros has sentenced a top opposition figure to seven years behind bars for assault during a controversial referendum on changes to the constitution.It was the latest in a string of sentences handed down to political figures who opposed a series of constitutional reforms enabling President Azali Assoumani to extend his term in office.In a ruling late Monday, the security court sentenced Ahmed el-Barwane, secretary-general of the opposition Juwa party, for ordering an attack on a soldier during a July referendum on the reforms. It also handed 20 years jail time to another Juwa MP, Tocha Johar, who was also on trial alongside another 20 or so people accused of attacking a policeman. Two of the group were acquitted while the others were handed shorter sentences ranging from several months to three years. "The court's decisions cannot be appealed, which means they are violating the constitution and the international agreements which Comoros is a party to," said lawyer Azad Mze.At the weekend, the court handed down life sentences with hard labour to four senior opposition figures and lengthy jail terms to several others for plotting against the state.The opposition denounced the rulings as "an insult to democracy".Crackdown on the opposition Former vice-president Jaffar Ahmed Said Hassani, who fled to Tanzania, was sentenced in absentia to forced labour, while former army chief Colonel Ibrahim Salim was jailed.Hassani fell out of favour with the government in June for his open criticism of Azali's constitutional reforms, which were overwhelmingly passed during July's controversial referendum.The reforms allow Assoumani run for another term in office and overturn a five-year rotation of power between Comoros' three main islands to ensure political balance in this coup-prone country.Following the vote, the authorities launched a crackdown on the opposition, charging at least eight of them with plotting attacks on key government figures. Others have gone into hiding.Although Assoumani was democratically elected in 2016, the controversial referendum - and what critics say is his increasingly authoritarian rule - has provoked violent protests.In October, armed rebels in Anjouan island, a Juwa stronghold, fought a week of running battles with the army. The island had been next in line to take over the rotating presidency before the measure was scrapped. The Comoros islands - Anjouan, Grande Comore and Moheli - have endured years of grinding poverty and political turmoil, including about 20 coups or attempted coups, since independence from France in 1975.