Like clockwork, fighting has broken out once more in South Sudan.

For months, UN officials and observers have warned that a temporary lull in violence was brought on by the wet season, which renders large swaths of the country impassable, both for humanitarian convoys and military vehicles.

"November marks the beginning of the dry season," Brian Kelly, spokesperson for the UN Mission in South Sudan (UNMISS), told VICE News. "This is creating a great amount of dread or anticipation that things could flare up anew."

This week, battles raged for days in and around the contested oil hub of Bentiu, home to a UN site that shelters nearly 50,000 displaced South Sudanese. The city, like others, has changed hands so many times since war broke out last December that officials and experts have had difficulty keeping track of who is in control.

On Wednesday, rebels claimed they were in command of Bentiu. Friday, the government said it controlled the city. The UN could not confirm multiple accounts of civilian deaths, but said one child was killed this week within their camp.

In nearby Rubkona, where peacekeepers rescued 30 civilians from an airstrip on Friday, a rebel spokesperson said their forces had "embarked on a tactical withdrawal."

In a Friday dispatch from the UN camp in Bentiu, Dr. Erna Rijnierse said her Doctors Without Borders team had already performed nine surgeries on patients wounded in the latest fighting, including on a pregnant woman shot in the chest.

"It's difficult to move around safely inside the camp or even in the hospital, stray bullets are flying around from all directions," Rijnierse wrote. "At any time the shooting and shelling can start."

Doctors Without Borders — often the last NGO to leave conflict areas — says it has had to suspend mobile clinics outside the camp.

"This seems to mark a really large scale battle," Eric Reeves, professor of English at Smith College and expert on Sudan and South Sudan, told VICE News. "It's an area where the ground is not totally dried out — it shows some commanders are really itching to get the fighting starting again."

The rebels are a loose-knit coalition — often with unclear allegiances — comprised of predominantly Nuer elements who are mostly loyal to former South Sudanese vice-president Riek Machar. Opposition forces are battling government troops led by president Salva Kiir. Kiir is a Dinka, and the fighting has largely split the country along ethnic lines.

The International Crisis Group says more than two dozen armed groups — including the Ugandan army fighting on the government's behalf — are involved in the conflict.

The UN estimates that more than 10,000 people have been killed and nearly 1.9 million driven from their homes since December. UN officials say rape and other forms of sexual violence have become endemic and are used as weapons of war.

'Some commanders are really itching to get the fighting starting again.'

The specter of widespread famine also looms over the crisis. Already, more than 2 million people face starvation, according to the aid group Oxfam.

A series of peace talks and ceasefires beginning in January have proven utterly ineffective. During the UN General Assembly in September, Kiir didn't show up at a high level meeting on the conflict, drawing the ire of many diplomats.

"The whole basis for the conflict was a fallout between the two political leaders, but as months have gone by, unfortunately on the ground, it has played out as an ethnic conflict," Ellen Margrethe Løj, head of UNMISS, told reporters at a briefing in September. "So even if the two political leaders sign an agreement, a lot of reconciliation work will need to take place on the ground."

The US and the European Union have levied sanctions against military leaders on both sides, but so far the Security Council has only considered such a move. A comprehensive UN arms embargo has similarly been tabled.

In a statement this week, the US State Department said it was "determined to hold accountable those who choose violence, standing ready to place sanctions on those who obstruct peace."

On Thursday, the International Crisis Group released a grim assessment of the conflict, writing that the warring factions "are preparing for major offensives as the seasonal rains ease."

"Hardliners in both the government and the Sudan People's Liberation Army-In Opposition are entrenching their positions," the International Crisis Group wrote. "Powerful generals from both the government's Sudanese People's Liberation Army and the SPLA-IO have expressed their intention to fight on, even if the political leadership sign an agreement."

As the struggle drags on toward its one-year mark, one of the lingering questions is how rebel forces — initially armed with what they seized when they defected from the army — have been able to maintain supplies of weapons and ammunition. Reeves believes the answer lies to the north, in Sudan, where the government in Khartoum is eager to foment chaos in territory it formerly controlled.

The Sudanese government has already been linked to airdrops of assault rifles to rebels active in Unity State as far back as August 2012. Reeves believes Khartoum is providing not only arms, but sophisticated military intelligence to rebels, a claim that other experts told VICE News was plausible.

In September, Reeves leaked what is purported to be the minutes of an August 31 meeting of senior Sudanese staff discussing how to assist Machar, the former South Sudanese vice-president. Both current and former Sudanese politicians have confirmed the document is real, though VICE News could not do so independently.

"Sudan has always conducted war by trying to turn South Sudanese against South Sudanese," said Reeves. "During the war with the North, they were brilliantly successful at turning Dinka against Nuer. The point here is Khartoum looks on and sees the SPLA destroying itself, and creating a much weaker fighting force."

Sudan has long harbored plans to annex five contested border regions whose fate was never resolved after the South's 2011 independence vote. A split South Sudan would further those aims.

'It's very clear that both parties have a lot of weapons.'

The government in Juba has continued to spend its diminished oil revenues on arms purchases instead of humanitarian aid and social services. A Bloomberg report cited an estimate from an unnamed Western diplomat that South Sudan has now spent at least $1 billion on weapons and delivery systems.

"It's very clear that both parties have a lot of weapons," said Loj, at the briefing.

UNMISS is meanwhile tasked with caring for some 100,000 displaced people — a job the mission was not created to perform. Though their mandate allows them to intervene in fighting if civilians are in danger, overwhelmed peacekeepers have not done so thus far.

Kiir has expressed displeasure with the role of UNMISS, saying the mission should return to the focus on state-building it had when first established in 2011. Critics say a concentration on development prevented the UN and other non-state actors from accurately diagnosing the tensions already present at independence that led to the current conflict.