Japan’s opposition demanded on Tuesday that a rising figure in the ruling bloc retract comments comparing their party’s tactics in parliament to those of the Nazis in 1930s Germany.

Taro Aso, 67, an outspoken former foreign minister, made the remarks Monday in a meeting with the president of the upper house, the opposition Democratic Party of Japan and news reports said.

“Comparing the DPJ to the Nazis is a verbal abuse that completely lacks common sense,” said DPJ Secretary-General Yukio Hatoyama. “We demand a retraction, of course.”

Aso, considered a leading future candidate for prime minister, apparently was repeating past comments drawing parallels between the opposition’s recent boycott of parliament and Nazi tactics prior to taking power in Germany.

On Tuesday, he argued he didn’t mean to say the Japanese opposition favored policies similar to the Nazis, though he did not offer a full retraction.

“I only tried to raise a question about the absence of proper discussion in the upper house,” he told reporters.

“I was trying to explain that there have been many such cases in the past after parliamentary discussions were boycotted,” Aso said. “There were similar cases before World War II, and that’s what I used as an example.”

The DPJ took control of the upper house in elections a year ago, and have used their position to block or delay legislation passed by the ruling coalition-dominated lower house. They have also boycotted legislative action.

The LDP has not released a precise quote of Aso’s comments Monday in his meeting with Upper House President Satsuki Eda, but the party conceded that he urged the opposition to behave more responsibly in parliament.

Then, apparently hinting at the dangers of allowing an obstructionist party to control the government, a DPJ official speaking on condition of anonymity quoted him as saying: “In the past, Germany invited tragedy by letting the Nazis take power.”

Aso was named last Friday as secretary general of the ruling Liberal Democratic Party in a Cabinet reshuffle. He ran unsuccessfully last year for prime minister, and is widely considered the frontrunner to succeed the unpopular Prime Minister Yasuo Fukuda.

A brash political blue blood who is well-known for abrasive comments, Aso has been in trouble before. He was forced to apologize in 2001 after saying as economics minister that “the best country in the world would be a country where the richest Jewish people would want to live.”