Japan will rethink its international pledge to cut its greenhouse gas emissions by 25 percent by 2020 from 1990 levels, Chief Cabinet Secretary Yoshihide Suga said Thursday, indicating the nation may have to lower its goal.

Suga told a news conference that Tokyo will set a new target for cutting greenhouse gas emissions because the Fukushima nuclear crisis has made the original goal difficult to achieve.

Prime Minister Shinzo Abe is expected to instruct Environment Minister Nobuteru Ishihara on Friday to rethink the 25 percent cut target and work out new measures to curb global warming during a ministerial meeting on reviving the economy.

"We have argued that a 25 percent reduction is an unattainable target," Suga told reporters.