Forces may tighten security on a border.Logical formLearned from5 sentences. Security may be tightened for officials.Logical formLearned from5 sentences. Closures may be tightened.Logical formLearned from5 sentences. A grip may be tightened under a president.Logical formLearned from5 sentences. A country may tighten (asylum rules).Logical formLearned from5 sentences. Some airports may tighten security.Logical formLearned from5 sentences. A supreme-court may tighten limits.Logical formLearned from5 sentences. Officials may tighten restrictions.Logical formLearned from5 sentences. Some businesses may tighten a belt.Logical formLearned from5 sentences. Troops may tighten a siege of a palestinian (refugee camp).Logical formLearned from5 sentences. A treasury-department may tighten (economic sanctions) on a country.Logical formLearned from5 sentences. Security may be tightened at some (government telecommunications).Logical formLearned from5 sentences. (Helicopter gunships) may tighten a grip.Logical formLearned from5 sentences. Islamic radicals may tighten a grip on a country.Logical formLearned from5 sentences. American laws may tighten an embargo.Logical formLearned from5 sentences.