WORLD oil prices reached a three-and-half-month high yesterday after militants threatened to widen their attacks on Nigeria's oil industry, threatening to cut deeper into supplies from the world's eighth-largest exporter.

US crude surged more than two per cent to $65.53, then eased to $65.38.

The price is moving closer to its record of $70.85, reached on August 30, fired by Nigerian violence and Iran's duel with the West over its nuclear programme.

Yesterday's push above $65 came as militants behind a spate of kidnappings and attacks on oil facilities in the West African nation's oil-rich Niger Delta threatened to use more aggressive tactics against oil workers and their families from the beginning of next month.

The country's biggest foreign operator, Royal Dutch Shell, has already evacuated staff from some facilities.