A cargo plane carrying the bodies of 74 South Africans killed in Nigeria arrived in Pretoria on Sunday.

The South Africans died in September when a church's guesthouse collapsed. Seven bodies remain in Nigeria awaiting identification before they can be sent home.

The guesthouse was on a compound run by televangelist TB Joshua in Lagos. On September 12, the multi-story building collapsed, killing 116 people.

Investigators suspect that the addition of floors without reinforcing the building's foundation caused the calamity. Joshua claimed that a small plane had been circling the building, and the collapse may have been an attempt on his life.

Officials in South Africa complained that the Nigerian government did not rescue the trapped persons quickly enough, are not investigating the incident thoroughly, and are taking too long to release the bodies. Nigerian officials blamed Joshua's church, The Synagogue, Church of All Nations, for the delays.

"For the first three days of the incident, the church people were very hostile and prevented rescue officials' access to the site," Ibrahim Farinloyeh, a spokesman for Nigeria's National Emergency Management Authority told the AFP news agency.

Thanduxolo Doro, whose sister died in the collapse, called Nigeria's response to the tragedy an injustice.

"I call on the affected families to unite and advocate for the suspension of what's left of the diplomatic ties between Nigeria and South Africa," Doro wrote in an open letter.

South African President Jacob Zuma acknowledged that tensions are running high.

"This is a particularly difficult time for South Africa," he said in a statement. "Not in the recent history of our country have we had this large number of our people die in one incident outside the country.

"Our thoughts are with the families, friends and colleagues that have lost their loved ones in this heart-breaking tragedy," Zuma continued. "The whole nation shares the pain of the mothers, fathers, daughters and sons who have lost their loved ones. We are all in grief."

An investigation into the building collapse is continuing in Lagos.