Brussels: The shooter, who killed two Swedish nationals and injured a third person in a lone-wolf attack in Brussels, identified himself as a member of the terror group ISIS group, claiming responsibility for the attack in a video posted online, Al Jazeera reported on Tuesday.

According to Al Jazeera, the suspect fled the scene of the shooting incident on Monday night and was being searched by the Belgian police.

Eric Van Duyse, a spokesman for the federal prosecutor's office, said the investigation was focused on "a possible terrorist motivation for the shooting" after "a claim of responsibility was posted on social media".

Authorities said they were working to determine the veracity of the video.

"This person claims to be inspired by Islamic State," Van Duyse said, adding "The Swedish nationality of the victims was put forward as the probable motive."

According to Al Jazeera, the suspected assailant, calling himself Abdesalem Al Guilani, claimed on social media that he was "a fighter for [God]" and a "member of ISIL" (ISIS).

Two persons were killed in the shooting incident in central Brussels on Monday evening, CNN reported citing Belgian public broadcaster VRT.

The deceased were reportedly of Swedish nationality.

CNN, citing the Belgian media, reported that the suspect was yet to be brought to book and the motive behind the killings could not be determined either.

Following the shooting incident, Belgian Prime Minister Alexander De Croo conveyed his condolences to relatives of the victims of the Brussels attack.

"My deepest condolences to the relatives of this cowardly attack in Brussels. I am closely following the situation, together with the Ministers of Justice and Home Affairs from @CrisiscenterBE. We are monitoring the situation and ask the people of Brussels to be vigilant," the Belgian PM posted on X.

Meanwhile, President of the European Commission, Ursula von der Leyen, on Tuesday also conveyed her condolences over the loss of lives in Brussels to Swedish Prime Minister Ulf Kristersson.

"I want to express my deepest condolences to @SwedishPM Kristersson and the Swedish people who have lost two of their compatriots tonight," the EU President posted from her X handle.

"Our thoughts are with you at this difficult time," she added in her post.