Vienna police searching nine houses for weapons and other evidence linked to last month's rampage at a Sikh temple arrested a gunman after he allegedly opened fire on officers.
Police spokesman Michael Takacs said no one was injured in the brief standoff. Officers with the Austrian capital's special tactics police squad managed to quickly overpower the unidentified 33-year-old Indian man and take him into custody, Takacs said.
Authorities seized an undisclosed number of firearms and knives in Monday's raids, he added.
Asked what prompted the man to fire on police, Takacs said: "We're not ruling anything out." He declined to elaborate.
A Sikh preacher was killed and 15 other people were wounded, including a second Sikh cleric during the May 24 Gurudwara rampage in Vienna.
Investigators say fundamentalist Sikhs armed with knives and a handgun attacked lower-caste Sikhs who worship at the Gurudwara, touching off a brawl that in turn triggered riots in several cities in India.
Witnesses have told police the attackers had accused one or both of the preachers of being disrespectful of the religion's Holy Book.