Four Canadian soldiers were killed and eight others wounded Friday in two separate bombings in Afghanistan, Canada's top general in the country said. It was one of the deadliest days for Canada since its Afghan mission started in 2002. "Success in war is costly," Brig.-Gen. Jonathan Vance, the commander of Canadian troops in Afghanistan, said at a news conference in Kandahar. "We are determined to succeed so that Afghan lives improve, but the insurgents are equally determined to challenge and prevent Afghanistan from flourishing as the nation it so wants to be." He said two soldiers died and five were wounded in an explosion during a morning foot patrol in the Zhari district, west of Kandahar. He said an Afghan interpreter also died. Vance said two other soldiers died and three were wounded when a roadside bomb exploded in the Shah Wali Kot district, northwest of Kandahar.