Japan stepped up security measures Friday after the simultaneous terror explosions in London on Thursday.
Chief Cabinet Secretary Hiroyuki Hosoda said on the day that he has asked government officials to beef up security. Hosoda is currently taking charge in the government as Prime Minister Junichiro Koizumi is attending the Group of Eight summit in Scotland.
Foreign Ministry Press Secretary Hatsuhisa Takashima said Japan has received no intelligence of being under possible terror attack, though security measures have been strengthened.
The blasts ripped through London's subway system and destroyed a double-decker bus, killing at least 37 people and leaving hundreds injured.
An al-Qaida-linked group has claimed responsibility, saying that the attack was a retaliation for Britain's involvement in the US-led operations in Iraq and Afghanistan.
As a staunch ally of the United States, Japan is also deeply involved in the operations in those regions.
National Public Safety Commission Chairman Yoshitaka Murata and transport minister Kazuo Kitagawa separately pledged to double vigilance against possible attacks on public transportation networks such as railways and other places, Hosoda said.
Measures to be taken also include intensifying sea patrols by the Japan Coast Guard and the Maritime Self-Defense Force, tightening immigration scrutiny and increasing guards at crowded places such as the ongoing World Exposition in Aichi Prefecture, Defense Agency chief Yoshinori Ono said.
In Tokyo, the Metropolitan Police Department has dispatched extra police officers at major train stations and high-profile embassies such as those of the United States and France.