BEIJING - A school in south China has been closed after 30 students fell ill with swine flu, as the number of cases nationwide increased four-fold in the past two weeks, health authorities said.

The children, all from a primary school in Guangdong province's Dongguan city, fell ill with A(H1N1) flu at the end of last week, the provincial health department said in a statement posted on its website late Sunday.

Authorities closed Shipai Central Primary School for a week, and have quarantined those in close contact with the patients.

The health department said the students' symptoms were mild, but warned the risk of a partial epidemic was looming in the province. Guangdong neighbours Hong Kong, where many schools have been closed following swine flu outbreaks.

"At present, Guangdong is in a situation where both imported and domestic cases, as well as swine flu and seasonal flu, co-exist," the statement said.

"According to the pattern of the spread of the flu, there is a growing risk of disease outbreaks in more areas of the province, and even of a partial epidemic."

The province has so far reported 111 cases - the largest number in mainland China, according to the official Xinhua news agency.

A total of 414 people have fallen ill with A(H1N1) flu in China, of which nearly 200 have already recovered, the country's health ministry said on its website late Sunday.

This is more than a four-fold increase from two weeks ago, when the country recorded its 100th case. No deaths have been reported.

According to the latest World Health Organization figures, nearly 44,300 cases of swine flu have been reported worldwide, with 180 fatalities.