Iran strongly criticized Bahrain for extending the jail term of prominent Shia cleric Sheikh Ali Salman, secretary-general of the country's main opposition party, Al-Wefaq.
Foreign Ministry spokesman Hossein Jaberi Ansari said on Tuesday such measures against moderate political leaders will never help solve the current issues in Bahrain.
He emphasized that such moves would complicate Bahrain's problems and "ultimately serve extremists", Press TV reported.
Sheikh Salman was originally sentenced on June 16, 2015, to four years in prison after a trial described by Amnesty International as "unfair".
The Bahrain court charged him with "publicly insulting the Interior Ministry" and "publicly inciting others to disobey the law" in his speeches.
His appeal had been pending for eight months but the Supreme Court of Appeal increased Salman's prison sentence on charges of inciting violence and calling for anti-regime demonstrations to nine years from the original four.
The Al-Wefaq opposition group, headed by Sheikh Salman, denounced the court ruling as "unacceptable and provocative", saying it "entrenches the exacerbating political crisis" in Bahrain.
Al-Wefaq was Bahrain's largest parliamentary bloc until its 18 lawmakers walked out in February 2011 to protest violence used against demonstrators.
Amnesty International also on Tuesday lambasted Bahrain's decision to uphold the conviction of Sheikh Salman, saying, "Sheikh Ali Salman's conviction is clearly politically motivated and is designed to send a message to others that even legitimate and peaceful demands for reform will not go unpunished."
In recent years, Bahrain has tightened restrictions on freedom of expression with multiple arrests and harassment of opposition politicians and activists.
Bahrain, a close ally of the US in the Persian Gulf region, has been witnessing protests against the ruling Al Khalifa dynasty since mid-February 2011.
