ISLAMABAD - The chief minister of Pakistan's Baluchistan resigned on Tuesday to end 'instability' in the gas-rich province, his spokesman said, amid opposition efforts to remove him through a vote of no confidence. Nawab Sanaullah Zehri quit shortly before a provincial assembly session in which lawmakers were expected to table a motion to demand a vote to oust him. 'I can confirm CM Baluchistan tendered resignation following the spirit of democratic principles,' Jan Achakzai, Zehri's spokesman, said on Twitter. Resource-rich Baluchistan is plagued by violence, perpetrated by both Islamist militants and nationalist insurgents, who are fighting to keep a greater share of the revenues from gas and minerals in the province.