Four foreigners detained on suspicion of proselytizing Christianity in Libya have been accused of espionage, a senior security official said on Monday.

Libyan officials say that the group includes a Swedish-American, a South Korean, a South African and an Egyptian.

The police chief behind the detention, Abdel-Salam el-Barghathi, told the Associated Press that embassy officials have been allowed access to the four, but that the group has raised suspicions by refusing to meet any.

Speaking to the AP while in detention flanked by Libyan security officials, Egyptian detainee Sherif Ramsis said he was on a missionary trip to Libya to spread Christianity, but was not aware of espionage allegations against him.

Ramsis said he runs a print shop and frequently visits neighboring Libya. He acknowledged that he wants to spread Christianity there.

Officials said that the group was arrested last week in the eastern city of Benghazi with tens of thousands of Christian books, booklets and stickers, mostly directed towards children, in their possession.

Ramsis said that he did not request assistance from the Egyptian embassy in Libya because he assumed authorities would not assist him. Egypt is the Arab world's largest Muslim country and is also home to the largest Christian minority in the Middle East.

“Everything is in God's hand,” Ramsis said, admitting that he was in fact on a proselytizing mission in Libya.

Libya has just a handful of churches. Spreading Christianity was banned under the regime of Moammar Gadhafi, who ruled the majority Muslim North African nation for more than four decades until he was killed in the nation's 2011 civil war.

Following Libya's uprising, Islamist militants have grown bolder in the absence of a strong military or police force. Last September, an attack in Benghazi by suspected Islamist militants killed U.S. Ambassador Chris Stevens and three other Americans. The International Committee of the Red Cross temporarily suspended activities in Benghazi after its offices were attacked and its personnel accused of spreading Christianity last year.

The arrests also come as group of nuns who worked in Libya's east for nearly 90 years have suspended their work. (AP)