SINGAPORE — Japanese Defence Minister Gen Nakatani said on Saturday that Japan and South Korea agreed to expand an emergency communication system between their defense ministries, including adding a new direct line between defense ministers.

Tensions have been high in the region since early January when North Korea conducted its fourth nuclear test. It has followed that with a satellite launch and tests of various missiles, most recently a failed launch on Tuesday.

"What it means is that we will make use of phones for emergency communication, when security-related emergencies such as a missile launch occur, and communication and coordination between the defense authorities of the two countries are needed," Nakatani told reporters at the Shangri-La Dialogue, a regional security forum in Singapore.

He said such emergency phone lines would be expanded to include a new direct link between the two countries' defense ministers.

Nakatani said talks would continue on sharing and safeguarding sensitive information on Pyongyang's missile and nuclear programs.

Under the framework, South Korea would pass relevant information to the United States, with which Seoul already has a legally-binding pact to share and safeguard intelligence called General Security of Military Information Agreement (GSOMIA). The United States would then pass the information on to Japan.

It would work similarly the other way around since the United States has also signed a GSOMIA with Japan.

Some South Koreans have voiced concerns about signing a security pact with Japan, their one-time colonial ruler.

Besides historical issues stemming from Japan's annexation of the Korean peninsula that ended in 1945, ties have been chilled by a long-running territorial dispute over a group of tiny islets.

(Reporting by Masayuki Kitano in SINGAPORE; Writing by Elaine Lies; Editing by Tom Hogue)