Sudanese President Omar al-Bashir on Tuesday said he was "deeply worried" about the worsening violence in neighbouring South Sudan and the Central African Republic.
Fighting has gripped South Sudan for more than a week, after President Salva Kiir accused his former deputy Riek Machar, who was fired from the government in July, of attempting a coup.
The Central African Republic has also been gripped by unrest, with an estimated 1,000 people killed this month in Christian-Muslim fighting.
"We are deeply worried about the situation on our borders and in the Central African Republic," Bashir told journalists after a meeting with his Chadian counterpart Idriss Deby in Khartoum.
Bashir said he and Deby had agreed to cooperate on issues related to the Central African Republic, "which affect the security of Sudan and Chad."
Chadian troops in the African peacekeeping force sent to the Central African Republic have been accused of complicity with the Muslim Seleka ex-rebels who overthrew president Francois Bozize in March in the predominantly Christian country.
Fighting in South Sudan has intensified over the past week despite international peace efforts, affecting half of the country's 10 states.
Bashir said Sunday that "the role of Sudan is to support these countries in achieving stability."
And Sudan's Information Minister Ahmed Bilal Osman on Friday said he was worried about the fate of oil flows which South Sudan pays cash-strapped Khartoum to move through northern pipelines for export.
He also feared an influx of refugees and guns from the unrest in South Sudan, which became independent less than three years ago under a 2005 peace deal that ended 23 years of civil war.
Oil-rich but poor, South Sudan won its independence in 2011 after its people voted overwhelmingly in a referendum to split from the north and form a new nation.