With the world's attention hyper-focused on fast-paced events in Iran and the effectively shuttered vital oil transit hub, the Hormuz Strait, some significant things were also happening around Taiwan this past week.

The US military confirmed that a P-8A Poseidon anti-submarine patrol aircraft transited the Taiwan Strait on Wednesday, a move that predictably drew Beijing's attention.

China said it monitored the US Navy aircraft as it passed through the narrow waterway separating Taiwan from mainland China.

"By operating within the Taiwan Strait in accordance with international law, the United States upholds the navigational rights and freedoms of all nations," the US 7th Fleet said in a statement, adding the transit "demonstrates the United States' commitment to a free and open Indo-Pacific."

The latest fly-through comes just weeks before President Donald Trump is scheduled to travel to Beijing for talks with Chinese President Xi Jinping aimed at hammering out a new trade agreement.

But the diplomatic backdrop is already showing strain, with regional media including The Japan Times saying that Beijing has grown irritated with Washington for failing to engage in serious advance planning ahead of the summit.

China is also without doubt angered as its Iranian oil imports are in extreme jeopardy due to Trump's Iran war, and recent bombing of Kharg Island export depot.

Against that backdrop, the Taiwan Strait patrol looks like a familiar piece of strategic signaling - a reminder to East Asian allies that even as Washington pours military resources into the Middle East, it still intends to project power in the Indo-Pacific.

And yet if China were to invade Taiwan tomorrow, there's likely not much Washington could do about it at a moment it is concentrating its firepower and resources on regime change in Iran, alongside its Israeli ally.