Pompeo touched down on the paradise island of Pohnpei where he will spend a few hours meeting leaders from Micronesia's Federated States, as well as neighbouring micro-states like Palau and the Marshall Islands.
The diplomatic courtship follows a visit by Pacific Island leaders to the White House earlier this year, part of America's drive for a "free and open" Indo-Pacific to counter China's increasingly muscular and expansionist policies.
"It's still a major strategic area, and this isn't new," said a senior State Department official noting past ties. "Now, the level of interaction is clearly elevated."
Elizabeth Economy of the Council on Foreign Relations told AFP that over the past year, the US had "worked aggressively" to shore up its position in the Pacific Islands region, considering it "of significant strategic interest".
Hugging the equator, the Federated States of Micronesia are scattered along nearly 3,000 kilometres (1,900 miles) of the Pacific, a significant area given Sino-American disputes over freedom of navigation in ocean waterways.
- Duelling charm offensives --
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Washington is no stranger to the Federation -- which brings together four island states and more than 600 islands and atolls -- thanks to a compact that guarantees US development aid and military protection.
Formerly part of the Caroline Islands, which were American trust territories, the federation signed a Compact of Free Association with the United States on gaining independence more than three decades ago.
Those agreements are set to be renewed in coming years.
In the meantime, China has launched a regional charm offensive that has alarmed the Trump administration, offering infrastructure loans and seemingly trying to have the Marshall Islands and Palau break off diplomatic relations with Taiwan.
"The United States can no longer afford to take the Pacific Islands for granted," said Economy.
At times the United States has looked to these island states at the United Nations -- when their voice is equal to any other state -- in looking for support for issues such as recognition of Jerusalem as the capital of Israel.
But the major point of difference remains climate change, an existential challenge for low-lying nations but a trend that the Trump administration has variously dismissed as a hoax or unimportant.