Karlsruhe/Berlin (dpa) - The man who attempted to carry out a massacre at a synagogue in the German city of Halle earlier this week has confessed to the crime and admitted having a right-wing extremist and anti-Semitic motive, dpa learned on Friday.

The 27-year-old, who has been named by authorities only as Stephan B under German privacy laws, made the confession during a hearing lasting multiple hours with an investigative judge at Germany's Federal Court of Justice.

The lone gunman tried and failed to storm the Jewish place of worship in the eastern German city on Wednesday. Fifty-one people were in the synagogue celebrating Yom Kippur, the Jewish Day of Atonement regarded as the holiest day of the year.

He then killed a 40-year-old woman in front of the synagogue and a 20-year-old man in a nearby kebab shop. Two other people - a couple - sustained serious gunshot wounds and remained hospitalized on Friday after undergoing surgery, a hospital spokesman said.

The incident is being treated as a right-wing extremist terrorist attack.

Stephan B is under arrest and has been charged with two murders and seven attempted murders. Investigators believe he wanted to commit a massacre and instigate others to carry out similar attacks.

The debate in Germany over what consequences should follow the attack was in full swing on Friday.

German Defence Minister Annegret Kramp-Karrenbauer, who also heads Chancellor Angela Merkel's Christian Democratic Union (CDU) party, called for stronger security laws and an extensive review of the security concepts for Jewish institutions in Germany.

"Right-wing terrorism is a truly existing problem in Germany," she said during a visit to the Latvian capital Riga, adding that the country had long underestimated the threat.

Interior Minister Horst Seehofer wants to speed up an already planned reform to improve the fight against right-wing extremism, while Family Affairs Minister Franziska Giffey announced that she wants to increase the resources for work against anti-Semitism.

Some mainstream politicians have linked the increase in right-wing extremist violence in the country and the rise in popularity of the far-right Alternative for Germany (AfD) party, which was founded in 2013 and entered parliament in 2017.

The government's anti-Semitism commissioner, Felix Klein, accused the AfD of fuelling hate against Jews, telling the broadcaster ZDF that the party has "many anti-Semitic positions."

But AfD leader Joerg Meuthen accused other politicians of instrumentalizing the attack for political reasons. He also slammed the security authorities for "failing."

Stephan B had four guns and several explosive devices with him during the synagogue attack.

Investigators found a 3D printer at the suspect's home, underpinning the suspicion that he made his own weapons. They also seized a hard drive, sources said.

Stephan B filmed his deeds with a helmet camera and broadcast them on the internet. He also wrote an 11-page "manifesto" that in some parts reads like the instructions for a computer game and abounds with anti-Semitic terms.

Experts said the hate messages do not indicate a complex ideological foundation. Instead, there are stronger references to the gaming subculture, for instance to the game "Counter-Strike - Global Offensive."

Former domestic intelligence head Hans-Georg Maassen said he sees a newer form of right-wing terrorism in the attack.

"We are not dealing with the standard Nazi here," Maassen told the broadcaster Welt. "To say after such an attack that we have to do more against right-wing extremism, against right-wing terrorism, falls short."

The Halle attack was the latest example of "an extremely disturbing rise in violence directed at Jews" in many places, the UN Human Rights Office said, warning also of a "cross-fertilization" among various forms of violent extremism online and on social media.

"No society can consider itself immune from this form of viral hatred," UN rights spokesman Rupert Colville said in Geneva.

The head of the Jewish community in Halle, Max Privorozki, said on Friday that he had worried about people no longer coming to the synagogue out of fear. But some of those who witnessed the attack on Wednesday returned the day after, he said.

Germany's upper house of parliament, the Bundesrat, on Friday held a minute of silence for the victims of the attack.

Its president, Daniel Guenther, called for consequences following the "cowardly act." Everyone must ask themselves what more they can do to act against such hatred and must help prevent the spread of anti-Semitism and xenophobia, he said.

People in Halle also continued to mourn the victims of the attack on Friday, with more and more flowers and candles being placed on the city's market square, outside the synagogue in the Paulus district and in front of the kebab shop.

An ecumenical church service will be held in the city on Monday to honour the victims.