A court in Tanzania's capital has sentenced four men to life imprisonment for the gang rape and sodomy of a girl under the age of 18 in a case which caused outrage in the country.

Among the convicts are Clinton Damas, a soldier with the Tanzania People's Defence Force, and Praygod Mushi, a prison officer.

The other two convicts are Nickson Jackson and Amin Lema.

In addition to the life sentences, the four men have each been ordered to pay 1m shillings ($370; £275) to the victim.

A fifth suspect - a senior policewoman suspected of ordering the sex attack - is to be tried separately in October.

The case has triggered shockwaves in Tanzania, which is a highly conservative society.

Outside the Dodoma Resident Magistrate's Court on Monday, the men's defence lawyer, Godfrey Wasonga, said they were dissatisfied with the ruling, claiming that some legal provisions had been violated.

But several activists, celebrities, and human rights defenders have praised the court's judgment on social media.

A video of the gang-rape began circulating online in August, and soon afterwards police urged the public not to forward the footage so as "to avoid torturing the victim and her family".

The East African nation is struggling to deal with a surge in gender-based violence, with many cases going unreported, according to local media.

"Ignoring these issues will only lead to their increased occurrence in our society," warned the Legal and Human Rights Centre last month.

In recent weeks a police commander, Theopista Mallya, was removed from her post following controversial comments in which she linked the victim to sex work.