Seven Muslims detained in Ireland over a suspected plot to assassinate a Swedish cartoonist, allegedly masterminded by a self-styled "Jihad Jane", are facing another three days of questioning.

Four men and three women were detained in the south east of the country over an alleged international conspiracy to murder Lars Vilks, who controversially depicted the Prophet Mohammed with the body of a dog.

Two Libyan men and a woman, one Algerian man and a Palestinian woman had their periods of detention extended at a closed court hearing on Wednesday night while a US woman and Croatian man were ordered back into garda custody at a brief sitting on Thursday. They can be questioned until Sunday morning.

The group had been arrested on Tuesday in a series of raids by anti-terrorist units acting on intelligence from the CIA, FBI and European agencies.

A judge at Waterford District Court agreed to a special closed sitting to protect the investigation as US caretaker Colleen LaRose, who styled herself Jihad Jane in a YouTube video, was charged with plotting the murder bid. She was accused in the US on Tuesday of conspiring with jihadist fighters and pledging to commit murder in the name of a Muslim holy war, or jihad.

According to the US Justice Department, the 46-year-old, who also goes by the name Fatima LaRose, plotted with five others in South Asia, Eastern and Western Europe and the US to recruit men on the internet to wage violent jihad in South Asia and Europe.

They are also accused of recruiting women online to travel to and around Europe supporting violent jihad.

It is understood LaRose agreed to marry an online contact from South Asia so he could move to Europe. US prosecutors said she was ordered to kill Mr Vilks in a way which would frighten "the whole Kufar (non-believer) world".

The seven people held in Ireland, aged from their mid-20s to late 40s, can be questioned for another 72 hours when detectives can ask a judge to extend their detention for another 48 hours.

Some of those arrested in Ireland have been legally in the country for up to 10 years. It is understood at least one of the suspects is a naturalised Irish citizen while a number of others have attempted to claim asylum.