Oil prices steadied on Thursday after US President Donald Trump called on Opec to "get prices down now!", slowing an upward surge that has pushed the market towards four-year highs.

Brent crude oil was down 20 cents at $79.20 a barrel by 1:40pm GMT. US light crude oil was up 30 cents at $71.42 a barrel after rising nearly 2% on Wednesday.

The North Sea benchmark has been trading close to $80 a barrel, near its highest for almost four years, on expectations that US sanctions against Iran, Opec's third biggest producer, will reduce supply in world markets.