Libyan leader Col Muammar Gaddafi says the EU should pay Libya at least 5bn euros (£4bn; $6.3bn) a year to stop illegal African immigration and avoid a "black Europe".
Speaking on a visit to Italy, Col Gaddafi said Europe "could turn into Africa" as "there are millions of Africans who want to come in".
Italy has drawn criticism for handing over to Libya migrants it intercepts at sea, without screening them first.
Far fewer now reach Italy from Libya.
European Commission figures show that in 2009 the number of people caught trying to enter Italy illegally fell to 7,300, from 32,052 in 2008. The data was collected under the EU's Eurodac fingerprinting system.
Col Gaddafi has forged close ties with Italy since a friendship treaty was signed two years ago. It sought to draw a line under historic bitterness between Libya and Italy, its former colonial master.
"Tomorrow Europe might no longer be European, and even black, as there are millions who want to come in," said Col Gaddafi, quoted by the AFP news agency.
He was speaking at a ceremony in Rome late on Monday, standing next to Italy's Prime Minister Silvio Berlusconi.
"We don't know what will happen, what will be the reaction of the white and Christian Europeans faced with this influx of starving and ignorant Africans," Col Gaddafi said.
"We don't know if Europe will remain an advanced and united continent or if it will be destroyed, as happened with the barbarian invasions."
Audience of women
Col Gaddafi has long seen himself as a champion of African interests on the international stage and has hosted many summits with African leaders.
Mr Berlusconi made no immediate comment on Col Gaddafi's demand.
Italy has been carrying out joint naval patrols with Libya for the past year, intercepting illegal migrants at sea.
The BBC's David Willey says Col Gaddafi's visit to Rome was overshadowed by another controversial speech he made - to two groups of several hundred young Italian women, hired at a fee of 70 or 80 euros each from a local modelling agency.
He told them that Islam should become the religion of Europe and gave them free copies of the Koran, after he had lectured them for an hour on the freedoms enjoyed by women in Libya.