BAGHDAD (AFP) - Multinational forces in Iraq (news - web sites) said that more than a dozen missile warheads said to contain mustard gas or sarin have tested negative for chemical agents. Washington had announced the find by Polish troops on Thursday, which was later confirmed by Warsaw. The head of Poland's military intelligence service also said on Friday that "terrorist" groups were seeking to acquire the weapons. But the 122mm warheads, found in late June, have been found not to contain the deadly chemicals, a statement from multinational forces here said. "Those 16 rounds were all empty and tested...