Nepal's former rebel Maoist party has asked the United Nations to postpone the verification of the number of their fighters, after two party leaders were killed in the country's south. The United Nations was scheduled to begin checking the age and date of recruitment of Maoist fighters as part of the peace process. Liam Cochrane reports from Kathmandu.

The senior members of the Maoist-affiliated Young Communist League were killed in Nepal's central southern district of Saptari.

They were traveling with journalists and human rights workers Wednesday when a group stopped their vehicle and abducted them. The two were later killed, and one of the bodies was mutilated.

Police blame the attack on the Madheshi People's Rights Forum, but the group denies responsibility.

Nepalese Maoist rebels train at a camp in Makwanpur, south of Kathmandu (File)

It is the second time the Maoists have postponed the verification process, but a spokesman for the U.N. mission in Nepal, Kieran Dwyer, says the request was reasonable, considering the tensions in the south.

"This is a very particular matter and the Maoists are wanting to make sure, in their leadership here, that on the ground level their cadres are willingness to cooperate with us," said Dwyer. "They have told us that the sensitivities in the cantonments are extremely high and people are upset over these killings."

The Maoists' central committee is meeting Thursday to discuss how to react to the murders.

The Maoists fought a bloody 10-year insurgency to oust Nepal's monarchy. After the king lost power last year, other political parties invited the Maoists to join an interim multi-party government.

Under an agreement to bring peace to the country, the Maoists have moved 31,000 fighters to seven camps across the country and have locked up almost 3,000 weapons. The United Nations must verify that none of the troops are under 18 years old or were recruited after the peace process began.

The Maoists have not yet indicated how long they might postpone the verification of their troops, but Kieran Dwyer is hopeful that the process will move ahead soon.

"We would expect that verification process would begin in a couple of days," said Dwyer. "But of course we have to be aware that these sorts of killing were extremely serious matters in the peace process and that they serious erode the confidence of the parties in the process."

Nepal's southern districts have seen an increase in violence since a peace deal was signed between the Maoists and the major political parties last year, with dozens of politically motivated killings.