BEIJING, Jan. 10 (Xinhua) -- A Japanese astronaut living on the International Space Station (ISS) said his earlier claim that he had grown nearly 10 centimeters was false.

Norishige Kanai, a former diving medical officer in the Japan Maritime Self-Defense Force, wrote that he "had actually grown by as much as 9 cm" after a measurement in space on Tuesday.

"I'm a bit worried whether I'll fit in the Soyuz seat when I go back," he added in another tweet.

His words attracted 40,000 likes and 22,000 retweets. The news has drawn extraordinary international attention to his first expedition on board the ISS.

However, Kanai's later tweets said he was mistaken after measuring himself again and adjusting his new height increase to 2 centimeters to hit 182 centimeters.

According to past studies by NASA scientists, astronauts do get taller in space by about 3 percent, which means a 1.8-meter person could gain approximately 5 centimeters while in orbit.

It's known that the human spine stretches or expands while not exposed to the pull of Earth's gravity, allowing astronauts to grow taller.

Space experts point out the different range of growth depends on everybody's different physical responses.

Experts say the astronaut's height returns to normal after a few months back on Earth. In short, their growth is temporary.

However, it's rare for a growth of 9 centimeters. The returning space shuttle has a height or size limit for passengers.

To fit in a Soyuz seat, an astronaut should be no taller than 190 centimeters when standing and 99 centimeters when seated, according to NASA.

"Measurement errors? But it seems to have become a serious topic. I'm terribly sorry it's fake news," Kanai tweeted.