Washington, May 31: The United States today renamed its oldest and largest military command - the Pacific Command - to Indo-Pacific Command, in a largely symbolic move to signal India's importance to the US military amid heightened tensions with China over the militarisation of the South China Sea.

Henceforth, the storied US Pacific Command, or PACOM, which was formed after World War II, will be known as the US Indo-Pacific Command.

"In recognition of the increasing connectivity, the Indian and Pacific Oceans, today we rename the US Pacific Command to US Indo-Pacific Command," Secretary of Defence James Mattis said while speaking at a change of command ceremony in Hawaii, where the command's headquarters is located.

The Pentagon's move is also reflective of the growing importance of India in US strategic thinking.

India was granted the 'Major Defence Partner' status by the previous Barack Obama Administration, providing for transfer of technology and deeper cooperation in the defence sector. In 2016, India and the US had signed a crucial logistics defence pact enabling their militaries to use each other's assets and bases for repair and replenishment of supplies, making joint operations more efficient.

Soon after coming to power, the Trump administration had renamed Asia Pacific as Indo-Pacific and identified India as one bookend of the region.

"Over many decades, this command has repeatedly adapted to changing circumstance, and today carries that legacy forward as America focuses west," Mattis said in his remarks.

"It is our primary combatant command, it's standing watch and intimately engaged with over half of the earth's surface and its diverse populations, from Hollywood, to Bollywood, from polar bears to penguins," Mattis said of the command whose areas of responsibility includes 36 nations, including India, as well as both the Pacific and Indian Oceans.

Admiral Phil Davidson replaced Admiral Harry Harris as Commander, US Indo-Pacific Command or IndoPacom. Harris has been appointed as the US ambassador to South Korea. Referring to the 2018 National Defence Strategy which acknowledges Pacific challenges and signals America's resolve and lasting commitment to the Indo-Pacific, Mattis said America's vision is shared by most nations in the region.

"For every state, sovereignty is respected, no matter its size and it's a region open to investment and free, fair and reciprocal trade not bound by any nation's predatory economics or threat of coercion, for the Indo-Pacific has many belts and many roads," Mattis said in an apparent dig at China which is investing billions of dollars for its so called One Belt One Road initiative.

America continues to invest vigorously in Indo-Pacific stability, bolstering the free and open rules-based international order that has enabled this region to grow and thrive for over 70 years.

"While we are prepared to face any who would seek to challenge America's resolve, our National Defence Strategy is not a strategy of confrontation," he said. Mattis said the US will always be seeking peace from a position of strength. "We will also continue further strengthening existing alliances and fostering new partnerships in the region, for these form a fundamental cornerstone of our strategic vision, a shared vision respectful of all nations sovereignty, and allowing us to reinforce a resilient security architecture capable of confronting shared threats, be they terrorism or an inhibition of free trade or humanitarian disasters that can befall any nation," he said.

Observing that relationships with Pacific and Indian Ocean allies and partners have proven critical to maintaining regional stability, Mattis said the US stands by its partners and support their sovereign decisions, because all nations, large and small, are essential to the region if they are to sustain stability in ocean areas critical to global peace. The US move comes in the wake of a series of measures by China that have raised tensions in the South China Sea.

China claims almost all of the South China Sea. Vietnam, Philippines, Malaysia, Brunei and Taiwan have counter claims over the area. The US also rejects China's claims of ownership of the area.