Makeshift mortar-style launcher found outside U.S. base in Japan after 'attempted left-wing guerilla attack'

• Weapon consisted of two metal tubes connected to a simple timer
• Incident came hours after the arrest of senior member of ultra-left faction
• U.S. military's presence in Japan is highly controversial and resented
  

By Daily Mail Reporter

Published: 03:55 EST, 29 November 2013 | Updated: 11:37 EST, 29 November 2013

A makeshift mortar was found outside a U.S. airbase in Japan last night after two small explosions were heard nearby.

There were no injuries and no damage to the Yokota Air Force base in Tokyo, but investigations discovered what U.S. authorities described as an 'improvised launch device'.

The weapon consisted of two metal tubes dug into the ground, with their upper ends pointing towards the base, connected to a simple timing device.

Suspected left-wing guerilla attack: Tokyo police forensic investigators inspect a field near Yokota US air base at Tachikawa, west of Tokyo, where two makeshift rocket launchers were discovered last night

Suspicions have fallen on one of Japan's small ultra-leftist militant groups, with the incident coming just hours after the arrest of a senior member of a radical faction.

'The incident occurred at 11.30pm on Thursday. Flying objects were launched near the US military's Yokota Airbase,' a spokesman for Tokyo Metropolitan Police said.

'Several reports were made by neighbours that they had heard explosions at about 11:30 pm. Police discovered two steel pipes, two wires, batteries, and so forth.

'No damage has been reported so far and police have not found the projectiles.'

Local media reported the pipes were buried in the ground, with the upper end pointing in the direction of Yokota Airbase.

A statement from the U.S. military confirmed the presence of 'an improvised mortar launch outside Yokota'.

'There were no injuries and thus far we have found no damage or impact points here on base. We take matters of security at our installation very seriously and we are assisting' police, it said.

There have been no claims of responsibility, but police believe it may have been a guerrilla attack by extreme leftists, Jiji Press and other media said.

Police officers patrol near Yokota U.S. Air Force base: The weapon consisted of metal tubes dug into the ground, with upper ends pointing at the base. Left, a map shows the location of the base west of Tokyo

Broadcaster NTV reported police were concentrating their investigations on the Revolutionary Labourers' Association Anti-Majority Faction because the incident came just hours after they arrested a top-ranking member yesterday.

A similar incident occurred four years ago, when police raided hideouts of the same leftists, NTV said.

Pivotal infrastructure: Caroline Kennedy, the new U.S. ambassador to Japan, arriving at Yokota Air Base earlier this month

Japan's politics is generally moderate, although there are vestiges of the radicalism on both left and right that abounded in the Sixties and Seventies.

At that time Japan was in the middle of a decades-long period of blistering economic growth as the ruined and largely rural country that emerged from the Second World War rose to become the globe's second largest economy.

One of the most infamous groups was the United Red Army which, despite its small size, gained notoriety for its extreme brutality.

A linked group, the Japanese Red Army, operated from Lebanon in tandem with Palestinian militias, carrying out high profile terror attacks including a massacre at Israel's Lod airport and hijackings of Japan Airlines planes.

Japan is host to almost 50,000 U.S. service personnel and their families. The two countries have a mutual defence agreement that, in practice, means Tokyo is given shelter under Washington's significant security umbrella.

But many people in Okinawa, where the bulk of U.S. troops are based, resent their presence and an increasingly vocal campaign wants them to leave. However, reports of violence to this end are not common.

In a 2012 agreement, the U.S. said it would pull 9,000 Marines out of Okinawa as it seeks to ease a long-running standoff over the future of its huge military presence in one of its top Asian allies.

The planned Marine move, which is due to begin in the early 2020s, is part of a wider rebalancing of US military assets in the region under President Barack Obama's trumpeted 'pivot' to Asia.

Thursday's incident also comes as tensions run high in the region between China and Japan with the focus on a group of disputed islands in the East China Sea.