A lone gunman opened fire on a provincial Cabinet minister in eastern Pakistan on Tuesday, wounding her critically, police said. The attacker was quickly arrested after he fired a single shot at Zil-e-Huma, the Minister for Social Welfare for Punjab province, as she visited the city of Gujranwala, said Mohammed Nazir, a local police official. Huma had traveled to Gujranwala to meet activists of the Pakistan Muslim League, the ruling party at the federal and provincial level, of which she is a leader. "She is in a critical condition at the Government Civil Hospital, and officers are interrogating the attacker to determine why he attacked her," Nazir said. He provided no further details. Attacks on politicians are a regular occurrence in Pakistan, where rivalry between parties often boils over into violence. Gujranwala is 200 kilometers southeast of the capital, Islamabad.