Sudanese officials have indicated that the British teacher arrested for allowing her class teddy bear to be named Muhammad could be released soon.
Gillian Gibbons, of Liverpool, may face blasphemy charges for insulting Islam's Prophet. A conviction could mean six months in jail, 40 lashes or a fine.
The Sudan Embassy in London said the situation was a "storm in a teacup", based on a cultural misunderstanding.
British embassy officials have visited Ms Gibbons, 54, in Khartoum prison.
Prime Minister Gordon Brown said he understood that Ms Gibbons, who is now facing her third day in custody, had not been charged with any offence.
Mr Brown said consulate officials were in contact with Ms Gibbons' family, and that he felt "very sorry" about what was happening to her.
He said officials would continue to try to "clarify the position so that she can be released".
The toy was named in September after children were asked to vote on a name for a teddy bear as part of the class's study of animals and their habitats.
Several parents of children at the Unity High School, in Khartoum, made complaints to the authorities leading to Ms Gibbons' arrest on Sunday.
It is seen as an insult to Islam to attempt to make an image of the Prophet Muhammad.
But a seven-year-old pupil in Ms Gibbons' class at the Christian, fee-paying school has jumped to his teacher's defence.
BBC News Sudan correspondent Amber Henshaw said the boy had chosen the name because it was the same as his own, and he had no idea that it would cause offence.
He said that he liked Ms Gibbons and he hoped she would return to teach at the school.
Ms Gibbons has been suspended from her teaching post, and the school has closed until January.
Dr Khalid al Mubarak, a spokesman for the Sudan embassy in London, said he was confident that Ms Gibbons would be cleared quickly.
He told BBC News: "We have Christian schools in the Sudan, we have Christian teachers who teach Muslim children, which shows a great deal of tolerance.
"The vice-president of our country is a Christian, we have many ministers who are Christian, and historically we became Christians round about the same time as England.
"Our relationship with Britain is so good that we wouldn't like such a minute event to be overblown."
He said what was happening was standard procedure because one of the parents had complained and the police were bound to investigate.
He added: "I am pretty certain that this minute incident will be clarified very quickly and this teacher who has been helping us with the teaching of children will be safe and will be cleared."
Inayat Bunglawala, assistant secretary general of the Muslim Council of Britain, also said it appeared to have been a "quite horrible misunderstanding" and Ms Gibbons should never have been arrested.
There was no apparent intention to offend Islamic sensibilities or defame the honour and name of the Prophet Muhammad, he said.
Gillian Gibbons had been working in Khartoum since August
Louise Ellman, Labour MP for Liverpool Riverside, said Foreign Office officials were trying to calm things down.
Ms Gibbons, her constituent, was being held in reasonable conditions in custody but was upset by what had happened, she said.
And it was unclear how long it would be before Sudanese authorities decided whether to charge her, she added.
"I hope common sense does prevail and the situation can be seen as what it is - and not an intended insult but something that was misunderstood," said Ms Ellman.
The Liberal Democrats have announced that their former leader, Lord Steel, will use his meeting in Khartoum with Sudan's President Omar al-Bashir next week to call for the release of Ms Gibbons.
Fair Trials International said it was hard to say what the teacher, her family and supporters could expect because information about the Sudanese legal system was scarce.