The United States took a moment Tuesday to gather the great Asian democracies to its side to reassure them of the strength of their ties in the face of North Korean threats and an assertive China.

New threats from Pyongyang, ominous economic signals and China's aggressive stance on its territorial claims in the South China Sea and the Pacific have sent jitters through the region.

President Barack Obama's administration has long talked about a "re-balancing" in America's strategic focus, the so-called "pivot to Asia," but has often been distracted by crises elsewhere.

Officials say 21st century America will be as much a Pacific power as an Atlantic one, but in recent months Syria, Ukraine, Iran and Cuba have used up a lot of diplomatic bandwidth.

So on Tuesday in New York on the sidelines of the UN General Assembly, senior officials from the United States, Japan and South Korea met to renew their ties and show a common front.

Later in the day, Foreign Minister Sushma Swaraj of India, the world's largest democracy and a growing economic partner of the United States, was also to meet her US and Japanese counterparts.

"The primary purpose of this is to recognize that the region is going through certain challenges, but also faces major opportunities," US Secretary of State John Kerry said.

Kerry cited negotiations for the Trans-Pacific Partnership -- a major free trade deal -- as a great chance to deepen economic engagement, and North Korea's rogue regime as an immediate danger to the region.

Japanese Foreign Minister Fumio Kishida agreed, calling the security environment "very severe" and stressing the importance of the US-Japan and US-South Korea military alliances.

"Let us deepen further our three countries' dialogue today as well and cooperation over wide areas, including security," he said.

South Korea's foreign minister, Yun Byung-se, said the meeting came "at a very critical juncture, when the eyes of the world are set on the major challenges involving all of us."

He said the talks would send a "very clear" message to North Korea in particular not to provoke the allies.

- Rocket test -

On October 10, North Korea will mark the 70th anniversary of its ruling Workers' Party and there has been speculation for months that it will celebrate with a long-range rocket test.

Kim Jong-Un's pariah regime is under international sanctions, and Seoul and Washington have made it clear that they would see such a test as part of a banned ballistic missile program.

And even if the test does not take place, tensions remain high in the region, with Pyongyang periodically escalating its rhetoric and threatening all-out war against its neighbor.

US diplomats are loathe to describe their ties with the Asian democracies as a counter-balance to a rising China, but Beijing is the elephant in the room when the friends met.

Most of the countries of the Asia-Pacific have deep economic ties with China, but many also have disputes, in particular over its maritime territorial ambitions.

In recent months, Chinese construction crews have built air strips and docks on reclaimed islands in the South China Sea attempting to expand their control into disputed waters.

Last week, Obama welcomed his Chinese counterpart Xi Jinping to the White House and both men promised closer cooperation, as the world's great powers cautiously circle one another.

And even as the Chinese economy has stuttered, causing ripples through world markets, Xi has tightened his grip on power, purging corrupt officials and cracking down on dissidents.

Beijing remains a key partner in countering the North Korean threat, but its new assertiveness abroad risks throwing its delicately balanced US relationship out of kilter.