WikiLeaks founder Julian Assange handed himself in to British police on Tuesday after Sweden issued a warrant for his arrest over allegations of sex crimes, London's Metropolitan Police said.

Assange, whose WikiLeaks website is at the centre of a row over the release of secret US diplomatic cables, was arrested under a European Arrest Warrant.

Swedish prosecutors want to question the 39-year-old Australian about allegations including rape. He denies the allegations.

WikiLeaks, which has provoked fury in Washington with its publications, vowed it would continue making public details of the 250,000 secret US documents it had obtained.

"Today's actions against our editor-in-chief Julian Assange won't affect our operations: we will release more cables tonight as normal," WikiLeaks said, according to its Twitter page.

Assange is due to appear before City of Westminster Magistrates' Court in London later on Tuesday when a date for an extradition hearing is likely to be set. This must take place within 21 days of his arrest.

"He is accused by the Swedish authorities of one count of unlawful coercion, two counts of sexual molestation and one count of rape, all alleged to have been committed in August 2010," a London police spokeswoman said.

Assange has spent much of his time in Sweden and earlier this year was accused of sexual misconduct by two female Swedish WikiLeaks volunteers.   

This led Swedish prosecutors to open, then drop, then re-open an investigation into the allegations. The crime he is suspected of is the least severe of three categories of rape, carrying a maximum of four years in jail.

London police said Assange was arrested by officers from its extradition unit at about 9.30 am (0930 GMT) after he appeared by appointment at a police station. His whereabouts had been previously undisclosed.

If a judge is satisfied his extradition is warranted and will not breach his human rights, the WikiLeaks founder's extradition will be ordered, although Assange can appeal against that decision to higher courts.

Assange's Swedish lawyer has said his client would fight any extradition and believed foreign powers were influencing Sweden. - Reuters