South Korea and the United States upgraded their coordinated military surveillance status on Wednesday, a report said, ahead of an expected mid-range missile launch by North Korea.
Japan has deployed Patriot missiles in its capital as it readies to defend the 30 million people who live in greater Tokyo from any North Korean attack.
Foreign diplomats in Pyongyang huddled on Saturday to discuss a North Korean evacuation advisory as concerns grew that the isolated state was preparing a missile launch at a time of soaring nuclear tensions.
The United States said it was taking "all necessary precautions" after North Korea rang fresh alarms in an escalating crisis by moving a medium-range missile Thursday to its east coast.
The US Friday said it would bolster defenses against a possible North Korean missile strike a week after Pyongyang threatened a "pre-emptive" nuclear attack against its arch-foe.
Turkey lashed out against Syria as the death toll from a missile strike on Aleppo rose to 58 Sunday, while a US official urged the opposition to reconsider its boycott of international meetings.
The Syrian army's use of surface-to-surface missiles on Aleppo is part of a bid to advance on the northern city, swathes of which have fallen into rebel hands since mid-2012.
Two days after North Korea's nuclear test, South Korea touted Thursday the deployment of a new cruise missile capable of hitting targets in the North "anywhere, anytime".
South Korea plans to deploy Israeli-made precision guided missiles near its tense sea border with North Korea next month, including an island shelled by the North in 2010.
The Syrian regime has begun using missiles and barrel bombs against rebels, a top US official said Wednesday, signaling a dangerous escalation of the deadly 21-month-old conflict.
The United States has deployed naval ships equipped with ballistic missile defenses and is monitoring North Korea "very closely" ahead of an anticipated rocket launch.
Israeli and US defence officials have successfully tested the David's Sling missile defence system, completing the first phase of the weapon's development.
North Korea tried to export ballistic missile parts to Syria in May in violation of UN sanctions, Japanese media said Wednesday, citing diplomats who have seen a classified UN report.
North Korea has conducted motor tests to improve its long-range missiles after a failed launch in April, a US think tank said Monday after reviewing new satellite images.
The US could be vulnerable to attack from long-range ballistic missiles unless the government overhauls the country's "fragile" missile defense system.