TEHRAN, Jan 11 (Reuters) - Three strong explosions jolted southern Iran on Thursday, the semi-official Fars news agency reported, but it was not clear if there were any casualties. The cause of the explosions in Khorramshahr in the province of Khuzestan, which borders Iraq, was not clear, but a local journalist said they were controlled explosions to destroy land mines left in the area since the 1980-88 Iran-Iraq war.