The United States is not disengaging from Asia and is instead “digging in” to maintain ​a favourable balance of power in the Indo-Pacific, but ‌wants its partners to shoulder more responsibility for their defence, a senior Pentagon official said on Monday.

Seeking to counter concerns about Washington’s reliability, Elbridge Colby, ​Undersecretary of Defence for Policy, reiterated the US interest in ​the region as he called for greater burden-sharing and “partnership, ⁠not dependency”.

“America is definitely not disengaging from Asia,” Colby said ​in a speech in Manila. “We are not leaving; in fact, we ​are digging in to ensure a favourable balance of power where it matters most.”

The Philippines, the United States’ oldest treaty ally in Asia, is the first ​stop on a Southeast Asian trip that also will take ​Colby to Indonesia, Thailand and Cambodia.

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Colby said maintaining a favourable balance of power in the Indo-Pacific required a “posture of deterrence by denial along the First Island Chain” and pointed to what he described as a growing US military commitment in the region.

The First Island Chain refers to ​an area stretching ​from Japan down ⁠to Taiwan, the Philippines and Borneo.

The strategy could not rest on American forces alone, he said, ​arguing that allies should invest more in their security.

“When ​we ⁠ask our allies and partners to step up, to invest more in their own defence, and to take responsibility for their own sovereign ⁠security, ​we are not signalling abandonment,” Colby said. “We ​are looking for partners, not protectorates.”

“When our partners are strong, deterrence is strong,” he ​added.