For Ethiopia's Orthodox Christians, the ancient city of Aksum is a sacred place, home to the Biblical Queen of Sheba and Ark of the Covenant.

The ark is believed to contain the 10 commandments handed down to Moses by God, and is said to be under the guard of monks in the city.

Some Muslim groups are campaigning to build a mosque in the city - a suggestion rejected by Christian leaders, saying they would rather die. 

"Aksum is our Mecca," declares senior cleric Godefa Merha, who believes that just as churches are banned in Islam's holiest site, mosques cannot exist in Aksum.

"Aksum is a holy place. This city is a monastery," says Mr Godefa, the deputy head of Askum's Our Lady Mary of Zion Church.

This long-held position of Orthodox Christians is now at the centre of controversy as some Muslims are rallying under the banner "Justice for Aksum Muslims" to demand the right to build a mosque in the city, and to give their call to prayer - "Allah is the greatest" - on loudspeakers.

Many people see the controversy as unfortunate because the Kingdom of Aksum, one of the world's greatest ancient civilisations, was once famed for its religious tolerance. 

According to followers of both religions, Muslims first arrived in the kingdom soon after the advent of Islam in around 600AD as migrants fleeing persecution at the hands of Mecca's then non-Muslim rulers.

The Christian king welcomed them with open arms, and gave Islam its first presence outside the Arabian Peninsula. 

Today, Muslims make up about 10% of Aksum's population of around 73,000 inhabitants - with 85% of them being Orthodox Christians and the remaining 5% belonging to other Christian denominations. 

'Muslims forced to pray outside' 

Muslim resident Abdu Mohammed Ali, who is in his 40s, said his family has for generations rented Christian-owned homes to provide Muslims with places of worship.

This is the market in an area of Aksum where many Muslims live

"We have 13 temporary mosques. On Friday, if they [some Christians] hear us using loudspeakers, they say we are denigrating St Mary," he complains.

Aziz Mohammed, a traditional doctor who has lived in Aksum for 20 years, says some Muslims are forced to pray in the open because of the absence of mosques.

"Here, we, Muslim and Christian, live together. The Christians do not prohibit us from praying but for many years, many of us have been praying in the street. We need a mosque," he says.

The subject is clearly causing some tension between the communities. Mr Abdu was reluctant to talk to me, an Orthodox Christian, and only did so after much persuasion and checking my identity, while Mr Aziz, who was born to a Christian mother and Muslim father, refused to be drawn further on the subject, simply said: "Here you live fearing each other."

'We need to live in peace'

Similar differences surfaced in Aksum about 50 years ago when Emperor Haile Selassie was in power in Ethiopia.

The city's then-leader, a member of the royal family, struck a compromise which saw Muslims build a mosque some 15km (9.3 miles) away in the town of Wukiro-Maray.

Muslims in Wukiro-Maray, near Aksum, can choose from five mosques

During a visit to the town, which also has a majority Christian population, I met Keriya Mesud who was cooking for Muslim worshippers while they were praying. 

Pointing out that five mosques now exist in Wukiro-Maray, Ms Keriya said: "Though we need a mosque in Aksum, we can't force them. What we need is to live in peace."

Mr Godefa says the two communities do live in peace, adding that the people of the two Abrahamic faiths have much in common.

His best friend is a Muslim, he says, and they come together for weddings, funerals and other events.

'Only Christian hymns'

He believes that Muslims from other parts of Ethiopia are behind the campaign to build a mosque. 

But he vows that Orthodox Christians will never break the oath given to their fathers and grandfathers to preserve the "sanctity" of Aksum.

Kingdom of Aksum

- Became rich and powerful through control of Red Sea trade, lasting from around the 1st to the 8th centuries AD.

- Fremnatos - known as Frumentius in Europe - introduced Christianity, which was adopted as its official religion in 333AD

- According to local legend, the Queen of Sheba travelled from Aksum to Jerusalem to visit King Solomon

- Their son, Menelik I, is said to have brought back the Ark of the Covenant from Jerusalem after going to visit his father

- No-one is allowed to see the Ark in the Our Lady Mary of Zion Church

- Orthodox Christian churches must have a tabot, which is a replica of the Ark, to be recognised as a place of worship

- The ruins of the ancient city of Aksum are a UN World Heritage Site