World record holder Paula Radcliffe's tearful withdrawal from the women's Olympic marathon on Sunday was not due to injury, the British team said on Monday.

Radcliffe broke down in tears when she stopped after just over two hours' running on Sunday, after slipping back into fourth place.

The only thing she said at the time was "devastated". She was due to hold a news conference in Athens later on Monday.

"She was not injured," British team spokeswoman Emily Lewis told Reuters.

"We don't know what it was. She is seeing a doctor again this morning and then maybe we may be able to give a more definite reason. No decision has been taken on the 10,000 metres."

The Olympic women's 10,000 metres is being run on Friday.

Despite not running a marathon for 16 months, Radcliffe had been the favourite for Sunday's gold. But after she refused to speak to the media before the event, doubts about her fitness developed, with speculation over a calf injury.

British officials were so inundated with enquiries that they issued a statement insisting Radcliffe was fully fit.

After completing the historic course from Marathon to the Panathinaiko Stadium in an ambulance, Radcliffe told journalists only that she would "speak tomorrow."

It was a heartbreaking day for one of Britain's most popular athletes who has won an army of fans for her determination and willingness to keep going even in the face of some shattering defeats.

Four years ago she led throughout the Olympic 10,000 metres only to be overhauled with a lap to go, eventually finishing fourth.

The same thing had happened in the 1999 world championships when she managed a silver medal, but after moving up to the marathon and then shattering the world record in 2003 the hope was that she could finally add a major gold to her long list of victories on the road.

It was not to be, however, as Japan's Mizuki Noguchi took the honours and Radcliffe was left with nothing.