Japanese lawmaker Yoshitaka Sakurada called wartime sex slaves forced to work for Japan's Imperial Army "professional prostitutes". The remark has irked South Korea, which recently agreed to a landmark deal with Japan to settle the dispute.

The comments were apparently made by Sakurada, in a meeting with other Liberal Democratic Party members where he said the women were actually "prostitutes by occupation" but people have been "heavily misled" by propaganda treating them as if they were victims.

"Because (comfort women) are hesitant (to say) they were prostitutes, I suspect wrong perceptions may have been spread in Japan and South Korea," he said. Later, he apparently retracted his statement following a heavy backlash, and conceded his comments could be misleading and apologised.

Meanwhile, South Korea's foreign ministry called the comments reckless by a lawmaker who is "shameless in front of history". The ministry's spokesman, Cho June-hyuck, said the Japanese politician's comments were "nonsensical" and "ignorant". He said the victims have already been through a lot of pain and it is important that Japan creates an environment in which the landmark agreement can be executed smoothly.

A government source working on the ongoing peace efforts said Sakurada's remarks are not likely to affect progress in bilateral relations between the two countries.

The issue of "comfort women" or sex slaves during Japan's colonisation of Korea during 1910-1945 has been a major obstacle to better ties between Washington's two key allies. According to war historians, tens of thousands of women from around Asia, many of them Korean, were sent to front-line military brothels to provide sex to Japanese soldiers.

In December 2015, after decades of disregarding the issue, Japan agreed to a deal with South Korea to compensate tens of thousands of the victims. Japanese Prime Minister Shinzo Abe offered a formal apology and his government agreed to pay a compensation of ¥1bn yen (£5.6m, €7.56m) to the victims.