A Swiss radiology lab said Friday it will test the remains of the late Palestinian leader Yasser Arafat for polonium poisoning after receiving the go-ahead from his widow.

The experts from the Lausanne University Hospital Center, which also got the green light from the Palestinian Authority, will travel to the West Bank to take samples from the body, a spokesman for the lab said.

Warders in a French jail where prisoners are allowed to grow their own produce have been left red-faced after the discovery of cannabis plants among the flowers and vegetables.

The plants, which had reached a height of around 80cm (two and a half feet) before being spotted at the weekend, were found in vegetable patches located in the exercise courtyard of the Saint-Martin-de-Re prison in the west of France, Christophe Beaulieu, a regional official of the prison officers' union, told Agence France Presse.

British Prime Minister David Cameron and U.S. President Barack Obama warned Wednesday they would be forced to consider a new course of action if Syria threatens to use chemical weapons on rebel fighters.

The two leaders agreed during a telephone call that "the use -- or threat -- of chemical weapons was completely unacceptable and would force them to revisit their approach so far," Cameron's Downing Street office said.

France strongly condemned on Wednesday the clashes that erupted in the northern city of Tripoli between the rival neighborhoods of Bab al-Tabbaneh and Jabal Mohsen.

The French Foreign Ministry said in a statement: “The clashes are the result of historic disputes that have only been highlighted due to the developments in Syria.”

France is providing the Syrian opposition with "non-lethal" military aid, Prime Minister Jean-Marc Ayrault said Wednesday.

Speaking on BFMTV-RMC radio, Ayrault said France had responded positively to a request for help from the rebels seeking to overthrow Syrian President Bashar Assad.

Madonna dropped from her last concert in Europe Tuesday a swastika that outraged France's right-wing party but again demanded the freedom of jailed Russian girl punk band Pussy Riot.

The video that accompanied the pop icon's performance in Nice of "Nobody Knows Me" still showed National Front leader Marine Le Pen, but a question mark replaced a swastika that had previously flashed on the politician's forehead.

The Syrian National Council, Syria's main opposition group is studying the formation of a transitional government, its leader Abdel Basset Sayda said Tuesday.

"We are currently studying the formation of a transitional government," Sayda said after meeting French President Francois Hollande in Paris against a background of hints from the Syrian regime that President Bashar Assad could soon step down.

France on Tuesday added its voice to mounting international concern over the arrest on blasphemy charges of a young Christian girl in Pakistan.

The girl, Rimsha, is reported to have Down's syndrome. She faces the death penalty for allegedly burning pages with verses from the Koran.

French President Francois Hollande was due later Monday to meet with the new United Nations peace envoy to Syria, Lakhdar Brahimi, Hollande's office said.

Brahimi, a veteran diplomat troubleshooter, was named on Friday to take over from Kofi Annan after Annan quit because of the lack of international support for his peace plan.

Add corn and they're scandalized. Shallots are a sacrilege. Green beans and potatoes, unacceptable.

Meet the defense committee for France's Salade Nicoise -- possibly the world's most ubiquitous salad dish after Caesar salad -- that purists are tired of seeing tossed the "wrong" way.