LONDON: The battle for the US presidency has entered new territory with both candidates turning to scientific journals to set out their election promises.

In interviews in Thursday's issue of Nature and Friday's Science, George Bush and John Kerry outline their positions - from whether the US should build nuclear weapons to global climate change.

The arguments are mostly well-established but their engagement with the scientific establishment is revealing. The most divisive issue is stem cell research.

Mr Bush froze federal funding for research on embryonic stem cell lines created after 2001 in a move that incensed many biologists who felt such research represented the future.

Mr Bush tells Nature he is "committed to pursuing stem cell research without crossing a fundamental moral line". Mr Kerry says he would lift the "ideologically driven" limits by overturning the ban on federal funding of research on new stem cell lines.

He is also direct on nuclear weapons: "I would end the pursuit of a new generation of nuclear weapons." In contrast, Mr Bush points to his budget plans for 2005, which contain allowances for an increase in weapons activities.

He says: "The nuclear posture review release by my administration in January 2002 noted that the nation's nuclear infrastructure had atrophied since the end of the cold war and that the evolving security environment requires a flexible and responsive weapons-complex infrastructure."

He calls climate change "a serious long-term issue" and says he wants to sequester carbon and alleviate the rise in greenhouse gas emissions in partnership with other countries.

Mr Kerry says: "I will take the United States back to the international negotiating table while working at home to take concrete steps to reduce pollution, setting concrete limits to halt and reverse growth in global warming pollution and tapping the ingenuity of American industry." - Dawn/The Guardian News Service.