Solingen: The police have arrested a suspect in connection with the knife attack in Solingen, DW News reported, citing Interior Minister of North Rhine-Westphalia, Herbert Reul.

Reul told German TV that a "real suspect" who police had been looking for all day has been nabbed, but didn't clarify whether he was talking about one of the two people who had already been arrested.

He further said the man was "highly" suspected of the crime and that evidence had been found.

"I myself am a bit relieved at the moment," the minister said. "I can only tell you that it is now more than a hunch. Not only did we have a lead on this person, but we've also found pieces of evidence."

The arrested suspect's clothes were dirty and covered in blood, German news magazine Der Spiegel quoted security sources as saying.

Three people were killed in the stabbing in Solingen and eight others were wounded, including four in critical condition on Friday evening.

The Islamic State (IS) group claimed responsibility for the deadly knife attack, DW News reported.

In a statement on social media, IS' Amaq media wing said the knifeman was a "soldier of the Islamic State" who targeted a "Christian gathering" in what it said was "revenge for Muslims in Palestine and everywhere."

However, these claims could not be independently verified, according to DW News.

The attack happened at the "Festival of Diversity" on a central square, the Fronhof. The festival is being held in the city over the weekend to mark the 650th anniversary of its founding.

The three-day festival started on Friday, according to the festival's website and it was supposed to include music, food, performances, and family-friendly entertainment.

Meanwhile, several German leaders have called for stricter gun laws after the incident.

Vice Chancellor Robert Habeck said, "We don't know whether the terrible crime in Solingen could have been prevented with stricter laws." He added that some tightening of weapons restrictions is simply right and necessary.

"More weapons-free zones and stricter weapons laws -- nobody in Germany needs cutting and stabbing weapons in public. We are no longer living in the Middle Ages," Habeck said.

Habeck, a Green, is among several German political leaders who have urged tighter weapons rules in the wake of the attack.

German Interior Minister Nancy Faeser of the center-left Social Democrats (SPD) has also called for significantly stricter weapons laws.

Justice Minister Marco Buschmann, from the liberal Free Democrats (FDP), said ministers will have to discuss new laws that "can further advance the fight against this type of knife crime."

Notably, his party had previously opposed restrictions put forward by its coalition partner, as reported by DW News.

(With Inputs From Agencies)