SANAA/ADEN (Reuters) - Yemeni President Ali Abdullah Saleh Saturday reiterated that he would remain in power until his term ends in 2013, rejecting an opposition plan for him to step aside this year. "The peaceful and smooth transition of power is not carried out through chaos but through the will of the people expressed through elections," an official source at the presidential office said in a statement. The opposition Friday said Saleh was sticking to an earlier plan to step down in 2013 but had agreed to a proposal by religious leaders to revamp elections, parliament and the judicial system. Saleh, an ally of the United States in its battle against an Al-Qaeda wing based in his country, has struggled to cement a truce with Shia rebels in the north and quell a budding secessionist rebellion in the south. Protests have taken place across Yemen, a country of 23 million which borders the world's top oil exporter Saudi Arabia. The protesters say they are frustrated with widespread corruption and soaring unemployment in a country where 40 percent of its 23 million people live on $2 a day or less and a third face chronic hunger. Earlier Saturday witnesses told Reuters three protestors were wounded Friday evening when Yemeni security forces fired into the air and used tear gas to disperse demonstrators at a sit-in in the southern port city of Aden. Protestors were dispersed after they had gathered at a square in the city's Sheikh Othman district following Friday prayers, the witnesses said. Possibly more than 100,000 protested Friday in one of the largest demonstrations in Sanaa yet and similar numbers rallied in Taiz, south of the capital, a Reuters reporter said. Security forces arrested 16 protesters in Aden on Saturday, as thousands continued to demonstrate in the south demanding the fall of the regime of President Ali Abdullah Saleh. The anti-government demonstrators were nabbed as police dispersed protesters who were gathering to hold a sit-in outside Al-Nur mosque in Aden, police said. Witnesses said police used tear gas and fired warning shots to disperse the protesters and that two demonstrators were wounded after being beaten with batons. Meanwhile, thousands of anti-government protesters took to the streets in the city of Ataq, in the eastern province of Shabwa, on the third consecutive day of protests, witnesses said. "People want to topple the regime," demonstrators chanted, echoing a slogan that has gripped many Arab capitals and that has already forced the presidents of Tunisia and Egypt to quit. An MP from the neighbouring Al-Bayda province announced Friday his resignation from the ruling party of Saleh in protest to using force against demonstrators. Ali al-Umrani announced his decision to quit the General People's Congress and join anti-government protests at an anti-Saleh demonstration in the capital, Sanaa. Another member of the GPC, prominent businessman Nabil al-Khameri, also announced his resignation to protest the violence.