Many experts say the effort is overdue, given military advances in China during the past two decades as America focused on counter-terrorism operations in Iraq, Afghanistan, Syria and elsewhere.
Defense Secretary Mark Esper made known his regret at having accompanied Trump to the presidential photo opportunity in front of St. John's on the day of the Lafayette Square confrontations.
The split between the president and his Pentagon chief came amid heightened tensions with Tehran following a US drone strike that killed Gen. Qassem Soleimani, the head of Iran’s elite Quds Force. Trump had twice warned that he would hit Iranian cultural sites if Tehran retaliates against the US.
The meeting in Riyadh, where Esper arrived late on Monday after an unannounced visit to Afghanistan, also took in defence issues and the current situation in the region.
US Defence Secretary Mark Esper met senior Mongolian leaders on Thursday in a rare visit to the strategically important nation as the Pentagon seeks to implement its strategy
Esper said that the numbers could fluctuate, particularly if European allies strengthen their presence in the country. Trump's abrupt announcement last month that he had ordered a full troop withdrawal drew angry rebukes at home and abroad.
"I am pleased to announce that Christopher C. Miller, the highly respected Director of the National Counterterrorism Centre (unanimously confirmed by the Senate), will be Acting Secretary of Defence, effective immediately."
The initiative, called the Guidance for Development for Alliances and Partnerships (GDAP), comes just two weeks before the presidential election that, if President Donald Trump loses, could see Esper replaced in January.
Lloyd Austin is planning to meet President Volodymyr Zelensky and Defence Minister Andriy Taran, less than two months after both came to Washington to meet President Joe Biden, seeking assurances of US support.