Aab called a short-notice press conference on Tuesday morning to inform the media about what happened, and about his decision.

The police stopped Aab after he was caught in a speed check doing 73 kilometers an hour instead of the allowed 50 (45 mph instead of 31).

At the time of the police's check, Aab had a blood alcohol level of 0.28. Aab said he "very deeply regrets" the incident, and that he wouldn't try to justify himself. "I've learned my lesson," Aab said.

The minister added that getting behind the wheel drunk is "entirely irresponsible." He indicated that he hadn't had a drink for quite some time before driving, and "wrongly assumed" that he was sober.

The lower limit of most European Union countries is 0.2 to 0.25, at which point fines have to be paid and the police issue warnings. Estonia has a zero-tolerance policy for drunk driving.

Jaak Aab's resignation could prove an issue for the government of Prime Minister Jüri Ratas (Center), as Aab is one of Estonia's most recognized experts for regional and rural affairs.

Aab was appointed in June last year after his predecessor, Mihhail Korb (Center), had to resign following unrest in the coalition caused by a statement he gave to Red Army veterans, saying that he didn't agree with Estonia's NATO membership.

Leading up to his appointment, Aab worked as the Center Party's secretary general. He is a former member of the Riigikogu and minister of social affairs (2005-2007). Aab has also been mayor of Võhma and chairman of the Union of Estonian Cities and has worked as an advisor to local governments in Finland in the past.