The head of the United Nations climate change panel (IPCC), Rajendra Pachauri, has stepped down amid sexual harassment allegations.

A spokesman for Pachauri told the IPCC that he had resigned from his position with immediate effect.

Indian police are investigating a complaint from a 29-year-old woman working in Pachauri's office in Delhi.

Pachauri has denied the allegations.

Lawyers for the woman say the harassment included unwanted emails as well as text and phone messages.

On Monday, the 74-year-old had pulled out of a high-level IPCC meeting in Kenya because of "issues demanding his attention in India", as an IPCC spokesman put it.

The IPCC has since confirmed that the meeting will instead be chaired by its vice-president Ismail El Gizouli.

Pachauri had chaired the IPCC since 2002. In 2007 he collected the Nobel Peace Prize on behalf of the organisation for its work in the scientific assessment of the risks and causes of climate change.