Chad on Monday announced it was shutting down its southern border with the strife-wracked Central African Republic until the conflict in the poor, landlocked nation is resolved.
"Chad is closing its common borders with the Central African Republic," the statement released on President Idriss Deby Itno's website said, while he was on a tour of southern regions that border with the CAR.
"You're less than 20 metres (yards) from the frontier with the CAR," Deby told people in the southeastern town of Daha, according to the website. "Be aware that as of today our border is hermetically sealed."
"For any Chadian who wishes to return home with his property, we will open the border wide. But apart from this precise case, nobody is authorised to cross the border until the Central African crisis is solved," he added.
The conflict in the neighbouring country mainly pits former Seleka rebels drawn largely from the Muslim minority, who seized power for 10 months in March last year, against vigilantes mostly from the Christian majority.
Fighters are regularly accused of crossing into Chadian territory, but armed groups from Chad are also accused of crossing the other way to stir up trouble in the CAR.
Between them, the rival Central African sides are accused of massacring thousands of civilians, while more than a quarter of the population of 4.6 million has been displaced or become refugees abroad, including inside Chad.
Chad on April 16 said it had withdrawn more than 800 troops who played a key role in an international African peacekeeping force in the CAR, known as MISCA, drawing down its strength of about 8,000 men.
Deby ordered the pullout after the United Nations said Chadian troops had opened fire in a crowded market in the CAR capital Bangui on March 29 in an attack that left around 30 people dead "without any provocation". Chad angrily said this allegation was defamatory.
On Monday, Deby also promised "to increase substantially the number of defence and security forces in this (southern) zone the better to ensure the safety of the population."
Most of those displaced in the CAR are Muslims, who constitute about a fifth of the population, while the majority of the 200,000 people who have fled abroad went either to Chad or Cameroon. Many of them originally came from these neighbouring countries.