Seven-year-old Nurul was said to be 'upset'

Prime Minister Goh Chok Tong has said the ban is aimed at promoting racial harmony.

Correspondents say the sensitive issue is testing community cohesion in Singapore, where race relations have come to the forefront since the arrests of more than a dozen suspected al-Qaeda-linked terrorists in December.

The suspended girls had been given until Monday to stop wearing the headscarves, but they ignored the deadline.

One of the girls, seven-year-old Nurul Nasihah, arrived at White Sands Primary School with her parents, where they spent 30 minutes talking to the head teacher.

Muslim rules

Afterwards her father, Mohamad Nasser, told reporters his daughter cried when she was told she might be unable to return to the school.

The PM says he is trying to promote racial harmony

"The principal hugged my daughter and told us she can still return on condition that we complied with the rules," said Mr Mohamad.

But he said his daughter would not go along with the government rule "at the expense of my religion."

However he said he would allow his daughter to remove the headscarf if the government gave written assurance that she would be allowed to start wearing it again when she reached puberty or secondary school.

For devout Malay Muslims, the tudung, or scarf, is obligatory once girls reach puberty.

Mr Mohamad said he would try to enrol his daughter in a Muslim school, though he said those schools were already full.

A third Muslim girl failed to turn up for school on Monday, and a fourth was given until next Monday to comply with the rules.

The parents of the four girls asked the head teachers in January for the girls to be given permission to wear the headscarves, but it was refused.

Racial and religious riots wracked Singapore in the 1950s and '60s. Since then government policy has focussed on avoiding racial and religious tensions between the ethnic Chinese majority and the Malay Muslim minority.