premise: President Jiang Zemin committed China to sign the UN convention on economic, social and cultural rights before the end of the year, and said a second UN convention on civil and political rights was under consideration.
  Human rights groups reacted guardedly Tuesday to Jiang's reported promise.
  "One has to see it as positive, but at the same time note that they (China) said the same thing at the same time last year. ... We would first like to see it happen," said Robyn Kilpatrick, Amnesty International's spokesperson in Hong Kong.
  Kilpatrick also cautioned that China had already signed up to other covenants, covering the rights of the child and elimination of discrimination against women and of the use of torture, but had still been repeatedly accused of abuse.
   What does Jiang's reported promise refer to?
hypothesis: committed China to sign the UN convention