Opec oil exporter Kuwait has unexpectedly shut down its ageing 200,000-barrel-per-day Shuaiba refinery for four days but exports are not affected, state news agency Kuna said.

A "technical malfunction" in a steam pipeline was responsible for the closure of the country's smallest refinery, Kuna said, adding that commitments towards clients would be met.

State refiner KNPC could not be immediately reached for comment. The firm runs country's three oil refineries which have a combined capacity of around 930,000 bpd.

Kuwait is the world's fourth-largest oil exporter.-Reuters