Swedish officials said Wednesday they're making last-minute attempts to quiz WikiLeaks founder Julian Assange over sex crimes allegations, most of which are set to expire by next week, but that he would still be wanted for questioning on accusations of rape.

Assange, who escaped a Swedish arrest warrant by taking refuge in the Ecuadorean embassy in London in 2012, is wanted on two allegations of sexual molestation and one of unlawful coercion which expire by Aug. 18 unless he is formally charged. A fourth allegation of rape is valid until 2020.

The 44-year-old Australian, who has denied the allegations, says he has no intention of going to Sweden for fear of being extradited to the United States because of an ongoing investigation into WikiLeaks' dissemination of hundreds of thousands of classified U.S. documents.

Karin Rosander, spokeswoman at Sweden's prosecution authority, said Assange and British authorities have agreed he be questioned in London but that prosecutors have not heard back from the Ecuadorean Embassy despite attempts to contact them in March and June.

The Ecuadorean embassy said in a statement Monday that "on no occasion has any representative of the Kingdom of Sweden presented themselves at the embassy in relation to the Assange matter." The embassy didn't immediately respond to requests for further comment Wednesday.

"Even though the prosecutor is obliged to drop the (three) cases that will expire ... the rape (allegation) still stands," Rosander said. She did not want to speculate if the prosecutor would abandon the prosecution altogether.

One of Assange's Swedish defense lawyers, Thomas Olsson, said that if the three cases are dropped "it will not change anything for Assange" as the arrest warrant remains in force.

"I believe the case should have been closed long ago because the evidence is weak," Olsson said.

Justice Ministry spokeswoman Cecilia Riddselius says Sweden and Ecuador have agreed to start talks on an agreement of mutual legal assistance but that it was unclear if it could open the possibility of questioning Assange at the embassy.