(Photo: Mohamed Nureldin)A South Sudanese worshipper arrives to attend Sunday prayers in Baraka Parish church at Hajj Yusuf, on the outskirts of Khartoum, February 10, 2013. Sudan's President Omar Hassan al-Bashir has said he wants to adopt a "100 percent" Islamic constitution now that the South has split off. The government says the new constitution will guarantee religious freedom, but many Christians are wary. They say authorities started a crackdown in December and it has been getting worse.

The worshiping space for Christians in Sudan is shrinking after the government ordered a ban on the construction of new churches in the mostly Muslim nation.

Sudanese authorities said there are already enough churches to cater to Christian spiritual needs.

A Sudan Council of Churches leader deemed the construction ban on churches as a curtailment of Sudanese Christians' freedom of worship and belief, provided for in the country's constitution.

The new measure followed the demolition of a church near the capital, Khartoum, earlier in July by local authorities, the BBC reported.

The report quoted the Sudanese Minister of Guidance and Religious Endowments Shalil Abdullah as saying the government had stopped issuing permits for the building of new churches.

He said the existing ones are enough for the Christians who remained in Sudan following the 2011 secession and independence of South Sudan, whose people are mostly Christians or followers of traditional African religions.

Shalil noted that majority of South Sudan's people are Christians, while their numbers in Sudan are small, StarAfrica.com reported.

Rev. Kori El Ramli, secretary general of the Sudan Council of Churches, told BBC's Focus on Africa program the government move caught him by surprise as church leaders always had a good relationship with the authorities.

"We are growing, we need more churches," El Ramli said.

He also disclosed that local authorities were also in the process of forcibly relocating Christians from a shanty area of Omdurman City to somewhere north of the city.

This means that, with the new ruling, the relocated Christians will have no church in their new home, he noted.

"We are citizens and the constitution says there is freedom of religion and worship so we are using this to get our rights," said the church leader.

He said Christians the government to grant them new tracts of land where they can build new churches.

El Ramli also said the government recently appeared to be "taking a more threatening stance towards Christians."

A workshop the church council held recently at the University of Sudan was halted by intelligence agents who accused those present of evangelizing, El Ramli told the BBC.

Sudan's in May sentenced to death a Christian woman, Mariam Yehya Ibrahim, who refused to renounce her faith, sparking international criticism.

A month later, she was later freed and reunited with her American husband.