Newt Gingrich, a US Republican presidential candidate, has taken a lead over his main party rival, Mitt Romney, in both national and Iowa polls - despite Romney's big advantage in money and organisation.

Gingrich's latest remark that Palestinians are an "invented people" may help his cause in the Iowa state, as it was aimed at more than 60 per cent republican supporters there who call themselves evangelical Christians, a heavily pro-Israel group.

Though none of the candidates have challenged the accuracy of his comments, some called it unwise.

Al Jazeera's Tom Ackerman reports from Washington.