Saudi Arabia has confirmed seven new cases of Middle East Respiratory Syndrome (MERS), adding as many as 36 infections in five days, a sudden spread of a disease without a cure that kills more than a third of the people infected.

MERS, a SARS-like novel coronavirus that emerged in Saudi Arabia two years ago, has infected 231 people in the kingdom, of whom 76 have died, the Health Ministry said on its website.

Another cluster of cases has been detected in the United Arab Emirates, and Malaysian health authorities said a Malaysian citizen had been confirmed as having the disease after he returned from pilgrimage in Saudi Arabia.

Yemen, which shares a border with Saudi Arabia, confirmed its first case on April 13.

Although the worldwide number of MERS infections is fairly small, the high fatality rate among confirmed cases and the spread of the virus beyond the Middle East is keeping scientists and public health officials on alert.

Of particular concern is that Saudi Arabia, the birthplace of Islam, is expected to receive a surge of pilgrims in July during the faith's annual fasting month of Ramadan, followed by millions more in early October for the Haj.

MERS has no vaccine or anti-viral treatment, but international and Saudi health authorities say the disease, which originated in camels, does not transmit easily between people and may simply die out.

Health experts have warned, however, that MERS has the potential to mutate.

With the sudden jump in the number of officially confirmed Saudi cases over the past two weeks, Saudi authorities last week issued several statements aimed at reassuring the public that there was no immediate cause for concern at the latest outbreak and that it had not met international definitions of an epidemic.

On Sunday they said that foreign experts would arrive in the kingdom to help the government seek a cure for the disease.

Rumors of unreported cases have circulated on Saudi social media in recent weeks. Last week, the kingdom's cabinet asked Saudi news organizations to report only those cases that are officially confirmed by the Health Ministry.