Japan, scheduled to host the Group of Seven summit in May, will further tighten security in response to the suspected terrorist attacks on Belgium's airport and subway system, Prime Minister Shinzo Abe said Tuesday.

"We will do our utmost to prevent terrorism," Abe told reporters after explosions rocked Brussels airport and a subway station, reportedly killing dozens of people.

Japan will also host a series of G-7 ministerial meetings starting April 10 in the run-up to the leaders summit on May 26 and 27 in Mie Prefecture.

Abe expressed outrage and shock over the deaths, saying "Terrorism can never be tolerated."

Abe also voiced Japan's "strong solidarity with Belgium and the European Union, which face difficulties right now," and pledged that the government will do its best to protect citizens overseas.

In an advisory, the Foreign Ministry warned Japanese nationals traveling to or staying in Belgium to refrain from unnecessary outings.