The head of the UN mission in Ivory Coast on Monday accused Laurent Gbagbo's regime of carrying out "hostile acts" against foreign diplomats, harassing peacekeepers and disrupting their supplies.
"As from December 15, President Gbagbo's camp began to increase hostile acts against the international community, including the diplomatic corps, impartial forces and UNOCI," UN envoy Choi Young-jin told reporters.
Choi is UN Secretary General Ban Ki-moon's special representative in Ivory Coast, and civilian head of a mission which includes the 10,000-strong ONUCI peacekeeping operation.
He accused Gbagbo's troops of blocking access to the Golf Hotel in Abidjan, where Gbagbo's presidential rival Alassane Ouattara lives under UN protection, and "on and off denying access to food and water supply trucks."
He repeated a report that six gunmen in military uniform opened fire on a UN patrol on the night December 17 to 18, and said the Gbagbo camp had sent young men to intimidate UN staff in their homes at night.
But the international community led by France started to implement number of sanctions starts by the European Union's move on Monday when it decided to slap visa bans on 19 Ivoirians, including incumbent president Gbagbo and his powerful wife Simone.
A spokeswoman for EU foreign policy chief said both Gbagbo and his wife were on the list.
Those listed for sanctions also include top presidential advisers, senior security officials and military officers, the head of state television.
The measures will take 24 to 48 hours before coming into force, with a decision to freeze assets for the 19 to be taken separately, diplomatic sources said.
The international community has stepped up pressure on Gbagbo to leave since his forces cracked down on supporters of his rival Alassane Ouattara, who has been recognized worldwide as the victor of the West African nation's presidential vote on November 28.
President Nicolas Sarkozy of France, the country's former colonial power, gave Gbagbo until the weekend to go to avoid being put on the EU list of Ivoirians targeted with visa bans and asset freezes.