Kabul, Kandah ¯ ar, Maz ¯ ar-e-Sharif, and Her ¯ at are the principal commercial cities of eastern, southern, northern, and western Afghanistan, respectively. The first two are the main distribution centers for imports arriving from the direction of Pakistan; the latter two, for materials arriving from Iran and the former USSR. Hours of business vary. The destruction of paved roads has severely constrained normal domestic trade in most rural parts of the country. Heavy fighting in Kabul has completely destroyed the city's infrastructure.