A second senior official of Japan's education and science ministry has been arrested on bribery charges. Kazuaki Kawabata allegedly accepted gifts in exchange for giving a favor to a medical consulting firm in Tokyo.

The Tokyo District Public Prosecutors' Office arrested Kawabata, the ministry's director-general for international affairs, on Thursday.

Kawabata is suspected of being wined and dined to the tune of 12,600 dollars from August 2015 to March 2017. During that period, he was on loan to the Japan Aerospace Exploration Agency, or JAXA.

Investigative sources say he is suspected of arranging for a JAXA astronaut to give a speech on the centenary of Tokyo Medical University in 2016 at the request of an executive of the consulting firm, Koji Taniguchi.

Taniguchi was served a fresh arrest warrant on suspicion of bribery on Thursday. He is alleged to have treated Kawabata to meals.

Taniguchi was indicted 2 days earlier, on a bribery charge in a separate case that also involved a senior ministry official. He allegedly acted as an intermediary between an education ministry bureau chief, Futoshi Sano, and officials of Tokyo Medical University.

Sano allegedly gave the university favorable treatment for a subsidy program in return for his son's enrollment.

Sano was indicted for bribery along with Taniguchi on Tuesday.

Both Kawabata and Sano started their careers in the mid-1980s at the former science and technology agency. The agency later merged into the education and science ministry.

Kawabata was one year above Sano in the ministry's seniority. They both served in the key post of general affairs section chief.