The Bush administration says the five permanent members of the UN Security Council and Germany have agreed to pursue further sanctions against Iran over its suspect nuclear program after it failed to meet a weekend deadline to respond to an incentives package designed to defuse the dispute. The State Department said the group decided in a high-level phone call on Monday that it had no choice but to seek additional punitive measures on Iran. Iran has told the lead European negotiator that it will provide a written response to the offer on Tuesday but a State Department spokesman said sanctions would come in the absence of a proper reply. The six countries gave Iran an informal two-week deadline last month to accept or reject a package of economic incentives in return for curbing its uranium enrichment, which many believe is aimed at developing nuclear weapons. Iran denies the charge but allowed the deadline to pass without any definitive response.