Dresden police and prosecutors said on Tuesday that they had arrested a 21-year-old Syrian in connection with a knife attack on a late-night tram in the city over the weekend. 

He was detained in the early hours of Tuesday, police said, and was put in investigative custody on suspicion of grievous bodily harm, among other offenses. 

The man in question had already been detained once before and was released soon after the incident, with no initial indication of him being directly involved in injuring a young American. But investigators said new information might implicate him more directly. 

Police said in a press release that after further investigation there was now reasonable grounds to suspect that he was "involved in the knife attack against the 20-year-old American and also himself injured the victim with a dangerous object."

Tuesday's statement made no direct mention of the second suspect, originally believed to be the prime culprit behind the injuries sustained by the American man. As of Monday afternoon, authorities in the eastern German state of Saxony were still seeking him and had appealed for help from potential witnesses.

US Embassy in Berlin calls for swift, severe punishment

The victim was wounded after stepping in to try to protect another female passenger on the tram who was being harassed, according to police.

The US Embassy in Berlin condemned the "brutal attack" in a statement online, and called on "German authorities to swiftly bring the perpetrators to justice and punish them to the fullest extent permitted by law." 

The victim was hospitalized with lacerations to the face but police said the injuries were not life-threatening.

Police and prosecutors said that their investigations were ongoing and that as a result of this they could not yet provide further details.

Edited by: Wesley Dockery