Explosions near U.S. Army base in Japan, no injuries reported

TOKYO, April 28 (UPI) -- Japanese police are investigating a possible small-projectile rocket attack shortly after midnight Tuesday at the U.S. Army's Camp Zama base near Tokyo.

There are no reports of injuries or building damage. The base is about 35 miles away from Tokyo. Residents heard explosions at about 12:40 a.m.

A Kanagawa prefecture police spokesman announced that two steel pipes about 2.5 inches in diameter were discovered planted in the ground with electric cables near Camp Zama. Projectiles believed to have been fired from the pipes were found later.

"There were no reports of explosions on Camp Zama and as of now, no evidence of explosions or impacts," Camp Zama officials said in a statement Tuesday. "The Army is cooperating with the local authorities in their investigation.

Kanagawa police suspect "left-wing extremists" are responsible for the attempted attack, according to Chief Cabinet Secretary Yoshihide Suga.

The U.S. Army Garrison announced it was "not aware any claims to responsibility for the explosions."

The explosions occurred soon after the U.S. and Japan announced a revised security agreement that expands the Asian country's role in it's alliance with the U.S.

President Obama and Japanese Prime Minister Shinzo Abe visited the Lincoln Memorial on Monday. Abe's visit was set for Tuesday, but he arrived one day early. The president decided to take the prime minister to a local landmark upon his arrival. This April marks 150 years since the end of the Civil War.

Abe is in Washington D.C. to discuss a range of economic, security and global issues, including progress on the Trans Pacific Partnership and climate change.