Slovak Prime Minister Robert Fico remains in serious condition and still faces risks of complications but has stabilized, officials said on Saturday, while the man accused of shooting him multiple times has been ordered to stay in custody.

The prime minister, 59, was shot at point-blank range in an attack on Wednesday that sent shockwaves through Europe and raised concerns over the polarized state of politics in Slovakia, a central European country of 5.4 million people.

"We have not won yet, that is important to say," Deputy Prime Minister Robert Kaliniak said, giving an update on Fico's condition in front of the hospital in the town of Banka Bystrica where the prime minister is being treated.

The Slovak Specialised Criminal Court ruled on Saturday that the suspect, identified by prosecutors as Juraj C., would remain in custody after being charged with attempted murder.

A court spokesperson said prosecutors said they feared he could flee or carry out other crimes if set free. The suspect can appeal the order to Slovakia's Supreme Court.

The suspect left the courthouse just hours after government ministers announced gave an update on Fico's condition.

Interior Minister Matus Sutaj Estok has said the suspected attacker, who was detained on the spot after the shooting, acted alone. The suspect had previously taken part in anti-government protests, he said on Thursday.

Prognosis initially 'very bad'

Kalinak said there was no need to formally take over Fico's official duties while some communication with the premier was taking place.

Fico underwent a two-hour operation on Friday that improved prospects for his recovery.

"We are succeeding in gradually nearing a positive prognosis," Kalinak said.

"In the initial hours, the prognosis was very, very bad, you know that shots into the abdomen are basically fatal, in this case (the doctors) managed to overturn this state and further stabilize the condition."

Fico still faced a "big risk" of complications, Kalinak said. "The body's reaction to a shooting wound is always very serious and brings (the risk of) a number of complications, which lasts for four to five days, which is today and tomorrow."

He said it was unlikely Fico could be transferred to the capital, Bratislava, in coming days.

About 100 Fico supporters, some carrying flowers, gathered on Saturday outside the F.D. Roosevelt University Hospital in the central city of Banska Bystrica, where the premier was being treated. He was shot outside a cultural centre as he greeted supporters in the town of Handlova. 

Local news media say the suspect is a 71-year-old former security guard at a shopping mall and the author of three collections of poetry.

Since returning for a fourth time as prime minister last October, Fico has shifted policy quickly in what opposition critics called a power grab. His government has scaled back support for Ukraine in its war with Russia, and is revamping the public broadcaster amid concern from critics about media freedom.