A vehicle packed with explosives blew up Wednesday in a busy market in the Afghan capital of Kabul, killing seven people and wounding 26, Tass said. The official Soviet news agency reported in a dispatch from Kabul that the blast demolished 16 stores and burned five cars. It provided no other information on the explosion. Tass also quoted the Afghan news agency Bakhtar as saying anti-Marxist rebels shelled the city of Gardez, capital of Paktia province, killing two civilians, wounding three and destroying 22 houses.