The new PM had already taken over the day-to-day running of Kuwait

The emir, Sheikh Jaber al-Ahmed al-Sabah, has given the job of leading the government to his brother, long-serving Foreign Minister Sheikh Sabah al-Ahmed al-Sabah.

It is the first time since Kuwait's independence that the prime minister has not also been crown prince.

The separation of the two roles is a key demand of reformers.

Bowing to pressure

Sheikh Sabah was already the country's de facto leader, as both the emir and the crown prince, his cousin Sheikh Saad al-Abdullah al-Sabah, are in poor health.

All three men are in their seventies.

Sheikh Sabah supports privatisation and globalisation and is keen to improve relations with other Arab nations, including those that supported the 1990 Iraqi invasion of the emirate.

Correspondents say that the decision to split the roles of crown prince and prime minister shows the emir is clearly signalling that he is listening to the reform camp.

And some commentators argue it opens the way to one day appointing a prime minister from outside the royal family.

Kuwait's ruling family has been under intense pressure - particularly from the US - to loosen its grip on power.

However, reformists campaigning for more accountability and political freedom were dealt a blow at elections earlier this month, when Islamists and traditionalists gained seats.

Nonetheless, the emir in the past has pushed for a more reformist agenda than parliament has been prepared to swallow.