BANGUI, Expressing concern over continued violence in the Central African Republic and the resulting massive new levels of displacement, the United Nations refugee agency has underscored the need to ensure that relief workers are not made targets of hostilities and are given the humanitarian security they need to carry out their mission.

Since May, fresh and fierce clashes between armed groups in the CAR have wrought increasing suffering, deaths and destruction of property, said Andrej Mahecic, a spokesperson for the Office of the UN High Commissioner for Refugees (UNHCR).

Many newly displaced people speak of having witnessed killings, robberies, lootings and kidnappings. Even after reaching safe locations, they often risk assault by armed groups, if they venture outside, he added.

According to the UN agency, the crisis, well into its fourth year, has left one in every two Central African in need of humanitarian assistance or protection to survive and, if left to fester, the violence could negate the progress towards recovery in the country.

The violence has also driven over half a million people from CAR to seek refuge in neighbouring countries and displaced an additional 600,000 people within the country.

The level of insecurity has also prevented UNHCR and other relief organizations to fully assess the full extent of damage or displacement from the recent violence.

Some of our planned humanitarian deliveries by air have also been delayed or blocked, due to the armed groups' presence [and] aid agencies, including UNHCR, are increasingly among those targeted by armed groups and have, in some instances, been compelled to temporary withdraw their personnel, said Mahecic.

Despite the challenges, we continue to help those displaced in areas like the Haute-Kotto provincial capital of Bria, which was at the centre of much of the displacement in the east, he added, noting that the UN agency's response is struggling due to lack of resources.

Earlier this year, UNCHR issued an appeal for $209 million for its operations within the country as well as to assist refugees from the Central African Republic in neighbouring countries. However, only 9 per cent of the appeal has been funded thus far.

The United Nations peacekeeping mission in Central African Republic is requesting about 750 more troops to help fill a "security vacuum" worsened by the withdrawal of U.S. special forces as violence surges again.

The additional troops are needed in the southeast after the withdrawal this year of U.S. and Ugandan troops hunting the Lord's Resistance Army rebels, according to a message from mission head Parfait Onanga-Anyanga to the U.N.'s head of peacekeeping operations in New York.

Hundreds of people have been killed since May and more than half a million people have been displaced as largely sectarian violence moves into parts of Central African Republic that were spared the worst of the fighting that began in 2013. International observers warn that the country is approaching the levels of violence seen at the height of the conflict in 2014.

U.N. Secretary-General Antonio Guterres said he wanted to "shine a spotlight on an under-reported emergency" in Central African Republic, which has seen a 37 percent increase in refugees and displaced people in the past three months.

Rebel groups control an estimated 70 percent of the country, according to international human rights organizations. The U.N. mission has acknowledged that its authorized force of 10,750 military personnel and 2,080 police is not enough in the country.

The request for more troops would increase the total of uniformed peacekeepers to about 13,500.

The fighting is mostly between predominantly Muslim ex-Seleka rebels and majority Christian anti-Balaka fighters over resources and trade routes in the countryside.

The existence of the Lord's Resistance Army rebel group in the region is also a concern. The U.S. and Ugandan militaries in pulling out of the hunt for the LRA said the group had largely been neutralized. However, leader Joseph Kony, who is wanted by the International Criminal Court for alleged war crimes, remains one of Africa's most-wanted fugitives. The U.N. has reported kidnappings by the LRA in the region since the pullout.

In his cable, Onanga-Anyanga wrote that "new actors are emerging to fill the security vacuum (in the southeast), creating upheaval in a once relatively calm region." Those include offshoots of the ex-Seleka and anti-Balaka fighters.

The additional peacekeepers, if granted, also may be used to push out the ex-Seleka rebel group Popular Front for the Renaissance of Central African Republic. Onanga-Anyanga's cable said the mission's force commander is "confident the armed groups can be ousted from Bria" town in the southeast.

U.N. peacekeepers earlier this year forced the ex-Seleka rebel group Union for the Peace in Central African Republic out of the central mining town of Bambari.