Sultan Al-Atwani, a leader in the Joint Meeting Parties (JMP) was attacked by armed men in Hadda district of the capital.
Sources said that armed men driving a Toyota vehicle attacked Al-Atwani while he stopped at a street round. They started hitting him and his body guards.
Al-Atwani was seriously injured and taken immediately to a hospital.
In return, the JMP's issued a statement against the attack, saying that it was carried out by the ruling party General People’s Congress (GPC).
Yemen’s opposition threatened on Monday to boycott parliamentary elections next April and called for protests against the ruling party’s plan to hold the poll without completing a political dialogue for electoral reforms.