The European Union ambassador to Sudan was attacked in his home in Khartoum on Monday, the bloc's top diplomat Josep Borrell said, as fighting between rival generals gripped the nation.
"A few hours ago, the EU Ambassador in Sudan was assaulted in his own residency," Borrell wrote on Twitter, without detailing any injuries to the envoy.
"Security of diplomatic premises and staff is a primary responsibility of Sudanese authorities and an obligation under international law," he added.
The European Union's ambassador to Sudan is 58-year-old Irish diplomat Aidan O'Hara. E.U. spokeswoman Nabila Massrali told AFP that he was "OK" following the assault.
"The security of the staff is our priority," she said. "The EU delegation has not been evacuated. Security measures are being assessed."
Ireland's deputy prime minister and foreign minister, Micheal Martin, said O'Hara was "not seriously hurt" but that the assault was "a gross violation of obligations to protect diplomats under the Vienna Convention."
"Aidan is an outstanding Irish and European diplomat who is serving the EU under the most difficult circumstances," Martin said. "We thank him for his service and call for an urgent cessation of violence in Sudan, and resumption of dialogue."
Fighting between the Sudanese army and a rival paramilitary faction has killed about 200 people and wounded 1,800 after three days of urban warfare.
The United Nations has called for an immediate ceasefire, and international bodies, including the European Union, have expressed grave concern.