NATO members' dispute over how to share the burden of combat responsibility in Afghanistan is escalating. AS defense ministers prepare to meet in Lithuania today, U.S. Secretary of State Condoleezza Rice and British Foreign Secretary David Miliband arrived IN Afghanistan on a surprise visit intended to highlight what Rice said was the need for more troops. Both countries have been urging other NATO members to share more of the combat burden in southern Afghanistan where the Islamist Taliban insurgency is strongest. Germany says it will send more troops to the north -- but that's it.