A prominent Nigerian preacher is under fire after one of his buildings collapsed in Lagos last Friday, killing dozens of people who were trapped inside, the Associated Press reported.

Several church tour groups were inside the four-story guesthouse belonging to the Synagogue Church of All Nations when it collapsed and killed 70 people, most of whom are believed to be South African nationals.

A lack of available information for family members in South Africa has led to accusations that the church and its leader, TB Joshua, is trying to deny responsibility for the tragedy, the AP reported.

The victims traveled to Nigeria seeking spiritual guidance from "Prophet" Joshua, a famed televangelist said to have healing powers though his hands. Supporters say they have seen him rid people of AIDS and other incurable diseases.

Joshua has alluded that Islamist extremists groups in Nigeria, such as Boko Haram, are the ones behind the attack. His TV station, Emmanuel TV, also aired footage of what it claimed to be a "strange aircraft" flying around the building in the moments before the collapse, according to the AP.

"Hard times may test me, they cannot destroy me," the preacher wrote on Facebook after the incident.

Though an official cause has yet to be determined, government officials believe the collapse is connected to the guesthouse's ongoing construction. The building was having two stories added when it crumbled to the ground, officials told the AP.

"We need to look at weather, because of the number of people needing to be accommodated, they added more floors without looking at the foundation," Bede Obayi head of Nigeria's Standard Organization inspection and compliance unit, told the AP.

Church officials have also been accused of hindering efforts to search for survivors buried underneath the rubble. But so far they have not responded to the allegations.