AMP DOHA, Kuwait, March 22 — Iraqi forces have been repositioning their surface-to-surface missiles and are expected to try further missile attacks against advancing American troops, senior American officials said today. The officials also disclosed that the missiles fired at Kuwait over the past few days have not been random shots but have been targeted, based on Iraqi intelligence about where American units were positioned.Allied warplanes are now involved in an intensive effort to strike the Iraqis' mobile missile launchers before they fire again. United States military officials say they bombed several Iraqi missile launchers last night. But the...