Hillary Clinton, the US Secretary of State, said the measures would discourage North Korean aggression but China responded angrily accusing America of "aggravating regional tensions". Relations have been especially tense since the sinking of a South Korean warship in March which caused the death of 46 sailors and suspicion is high ahead of joint US-South Korean naval exercises planned for next week. Mrs Clinton said that the new sanctions would limit the purchase and sale of arms, and freeze the assets of Pyongyang's isolated leadership, which is accused of allowing millions of the country's people to starve. Few specific details were given but the Secretary of State said they were designed to stop Pyongyang from selling weapons technology in return for hard currency that is then used to develop more weapons of mass destruction. She added that they were not directed at the North Korean people but at the "misguided and malign priorities of their government". "[The sanctions will] increase our increase our ability to prevent North Korea's proliferation, to halt their illicit activities that help fund their weapons programmes and to discourage further provocative actions," Mrs Clinton said. During an unusual visit to the heavily defended demilitarised zone that divides the two Koreas, the Secretary of State said the North could have a peace treaty, normal relations with the United States and an end to sanctions if it ended its belligerence and took irreversible steps to end attempts to build atomic weapons.