Three Christian humanitarian groups working in Somalia have been banned from the country by Islamic militant group Al-Shabab which accused them of proselytism.

In a statement released on Monday, Al-Shabab, which is considered a terrorist organization and has ties to Al Qaeda, accused World Vision, the Adventist Development and Relief Agency (ADRA), and Diakonia of spreading Christian ideology in Somalia and ordered them to leave the country immediately.

"Acting as missionaries under the guise of the humanitarian work these three organizations have been spreading their corrupted ideologies in order to taint the pure creed of the Muslim people in Somalia," the group said. "We warn other local aid agencies against taking up the operations or secretly partnering with the banned organizations, otherwise they will face appropriate disciplinary measures."

All three aid groups have been working in the country for more than 15 years and have provided assistance to hundreds of thousands of Somalis.

Somali Prime Minister Omar Abdirashid Ali Sharmarke was quick to condemn Al-Shabab's actions, saying that they reflect the group's disregard for the welfare of the country's people.

"There is absolutely no excuse for this action. These are agencies that came to help the thousands of people who need their help," a spokesman for Sharmarke told IRIN. "This is evidence, if any was needed, of Al Shabab's disregard for the welfare and wellbeing of the Somali people. They simply don't care."

Meanwhile, World Vision and the ADRA denied the accusations of proselytism, and say that Al-Shabab's orders will have an adverse effect on millions of needy people.

"World Vision is surprised and disappointed by the move based on false accusations of spreading Christianity," said Amanda Koech of World Vision Somalia.

"The move to close the organization's operations in Somalia is unfortunate, especially coming at a time when there are more than 3.6 million people in Somalia who need urgent humanitarian aid. Of those in need, 700,000 are children."

The ADRA claims that some 180,000 people will be directly affected by the stoppage of its work, which the group holds is not done to "further a particular political or religious standpoint" in accordance with the Code of Conduct for The International Red Cross and Red Crescent Movement and NGOs in Disaster Relief.

"Due to its global humanitarian work in more than 120 countries worldwide, ADRA has established a reputation for working in harmony with and respecting a broad array of cultures, traditions, and beliefs," the group said in a statement. "The positive impact of ADRA's contributions in all these countries validates the agency's heritage and belief in benevolent giving."

The ban comes just days after eight humanitarian workers in Afghanistan were killed on accusations of proselytism, according to the Taliban, which claimed responsibility for the attack.

Al-Shabab, which claimed responsibility for the recent bomb attacks in Uganda during the World Cup final, has had a history of being particularly aggressive towards humanitarian workers, having killed over 40 in its three years of existence.