A state of emergency, attacks by Boko Haram militants, and rebel incursions are bringing new humanitarian and security concerns to Chad - a landlocked central African nation that shares borders with some of the region's most unstable countries.
The state of emergency - which covers three provinces - follows an increase in inter-communal clashes in Ouaddai and Sila, in eastern Chad, and fighting between self-defence groups, rebel forces, and the national army around gold mines in the north.
Chad's President Idriss Déby announced that 5,000 troops would be deployed to the affected provinces, and effectively gave them the power to kill those deemed troublemakers - a plan rights groups say amounts to a "call to massacre civilians".
"If fighting persists between Arabs and (local) Ouaddaians ... you shoot 10 from each side to save the majority," Déby said.
A new wave of attacks from Boko Haram militants in western Chad has displaced roughly 40,000 people since January, while rebel groups opposed to Déby's regime are threatening its northern border with Libya.
In February, French warplanes intervened at Déby's request to prevent a convoy of rebels - led by the president's own disgruntled nephew, Timan Erdimi - advancing from the deserts of southern Libya towards the Chadian capital, N'Djamena.
Aid agencies say they are grappling with people fleeing conflict as well as an outbreak of measles and cholera, while erratic rainfall has increased food insecurity, contributing to a 23 percent spike in severe malnutrition among children under five in the first half of this year, over the same period in 2018.
The UN said the humanitarian situation in the country has "deteriorated significantly" in recent months, and some four million people will be in need of assistance this year. Only 43 percent of the needed humanitarian funding has been received, however, meaning that the funding shortfall could prevent people from getting help.
Déby has won five elections since coming to power in a coup in 1990. He enjoys significant diplomatic support from the West for his role in combating Boko Haram and other extremist groups in northern Mali.
But his poor record on human rights and a severe economic crisis due to falling oil prices has inspired protests and strikes in recent years, while internal threats are growing among members of his own relatives and family members.
"Déby feels he is losing control... that he and his security forces are overwhelmed by problems," said Richard Moncrieff, central Africa project director for the International Crisis Group.
Here is an overview of the humanitarian needs and challenges as security threats multiply and political dissent grows.
Why was a state of emergency declared?
Chad's army is considered one of West Africa's strongest, but Déby is struggling to contain spreading insecurity. Declaring a state of emergency sends a signal "to international players, to show that Chad is facing threats and needs support", said Jérôme Tubiana, a Chad-Sudan analyst for the Geneva-based Small Arms Survey.
The state of emergency covers the eastern provinces of Sila and Ouaddaï where skirmishes between herder and farmer communities - usually triggered when herders move livestock over a farmer's land - have left more than 100 dead since January and displaced more than 5,000 people in August.
Also covered is the northern province of Tibesti, which has seen an influx of miners, Chadian soldiers, and rebels since the discovery of gold deposits in 2012. Clashes between rival groups are common.
More than 3,000 migrants from Chad and further overseas have fled the vast desert area in recent weeks following military operations to close the mines, said Anne Schaefer, head of mission for the UN's migration agency, IOM, in Chad. Many require medical support and help returning home.
"IOM is providing voluntary return assistance on a very limited scale due to absence of dedicated funding," said Schaefer.
Tensions over the mines have been particularly high in the town of Miski, where the local Teda population feels N'Djamena has denied the community its share of the riches. Residents have formed a self-defence group that has clashed with Chadian troops and now resembles a "proto-rebellion", according to Tubiana.
The government has responded by imposing a months-long blockade on Miski, which aid workers say has impacted livelihoods in an area already facing "crisis" levels of food insecurity - the highest in Chad - according to US-funded famine monitor FEWS NET.
What's happening in the Lake Chad basin?
Boko Haram and a powerful breakaway faction, the Islamic State of West Africa Province, or ISWAP, have made a dangerous comeback in recent months in the Lake Chad region, which is shared by four countries including Chad.
Nigeria has been worst affected, but a string of attacks has also rattled Chad's western Lac province, displacing around 40,000 people since January, according to the UN.
At least 20 Chadian soldiers were killed in a cross-border raid in March - the deadliest of its kind inside the country - while the militants abducted more than 50 people in a single day in May and killed 13 civilians on another.
The group's resurgence shows that military efforts, led by the Multinational Joint Task Force - which brings together troops from four countries in the Lake Chad region - "have been insufficient", said Remadji Hoinathy, a senior researcher for the Institute for Security Studies (ISS), an Africa-focused think tank.
"There is a need for a holistic approach to the problem... addressing community grievances, governance problems... offering people possibilities to be resilient," Hoinathy said.
Assistance to affected areas has been sparse, with aid agencies receiving only 15 percent of what they requested for Lac province, said Belinda Holdsworth, head of office for the UN's emergency aid coordination agency, OCHA, in Chad. Newly displaced people lack shelters, clean water, and basic sanitation, she said.
"Even when we can access the people who need our help, we are very limited in what we can deliver," said Holdsworth.
Who are the rebels in southern Libya?
Chadian rebel groups have taken advantage of the chaos in neighbouring Libya to implant themselves in its desert south.
In February, one group, the Union of Forces of Resistance (UFR), drove deep into Chadian territory before French warplanes stationed in its former colony beat them back at Déby's request.
The airstrikes destroyed 20 UFR pick-ups, with many of the rebels later arrested and sentenced to hefty prison terms. This has "weakened the [UFR] threat for a while, but it has not definitively eliminated it", said Hoinathy.
"There are always possibilities for this group, or others, to reconstitute and present a threat to power," said the researcher, citing continued insecurity in Libya, and Déby's lack of control over northern Chad.
In late 2018, government forces also clashed with the Military Command Council for the Salvation of the Republic, a relatively new rebel outfit also based in Libya and seeking to overthrow Déby's regime.
Rebel groups have twice come close to toppling Déby, having reached N'Djamena in 2006 and 2008 before being pushed back.
What are the other humanitarian needs?
An epidemic of measles that started in mid-2018 has continued through the year, with more than 23,000 cases, while 51 cases of cholera have also been reported since July.
Erratic rainfall has impacted some farmers' crops, Holdsworth said, adding that the state of emergency - and subsequent border closures - could affect trade and livelihoods, as well as NGO operations. "We are responding to multiple crises, which are all growing in severity," she said.
With just 35 percent of the funds requested by the humanitarian community received as of August, Holdsworth said aid groups will soon struggle to have an accurate picture of what the needs are - let alone respond to them.
In a few weeks, IOM's Displacement Tracking Matrix (DTM), which monitors the movement of internally displaced populations, will run out of funds. Losing the tool would have an "immediate impact on our ability to deliver response to people that have moved", Holdsworth said.