US President Donald Trump has signed an executive order vowing to use all measures, including US military action, to defend the energy-rich nation of Qatar -- though it remains unclear just what weight the pledge will carry.

The text of the order, available on Wednesday on the White House's website but dated Monday, appears to be another measure by Trump to assure the Qataris following Israel's surprise attack on the country, targeting Hamas leaders as they weighed accepting a ceasefire with Israel over the war in the Gaza Strip.

The order cites the two countries' “close cooperation” and “shared interest,” vowing to “guarantee the security and territorial integrity of the state of Qatar against external attack.”

“The United States shall regard any armed attack on the territory, sovereignty, or critical infrastructure of the state of Qatar as a threat to the peace and security of the United States,” the order says.

“In the event of such an attack, the United States shall take all lawful and appropriate measures -- including diplomatic, economic, and, if necessary, military -- to defend the interests of the United States and of the state of Qatar and to restore peace and stability.”

Order Follows Netanyahu Apology Call
The order apparently came during a visit to Washington on Monday by Israeli Prime Minister Benjamin Netanyahu. Trump organized a call by Netanyahu to Qatar during the visit in which Netanyahu “expressed his deep regret” over the strike that killed six people, including a member of the Qatari security forces, the White House said.

Qatar's Foreign Ministry described the US pledge as “an important step in strengthening the two countries’ close defense partnership.” The Qatari-funded Al Jazeera satellite news network declared: “New Trump executive order guarantees Qatar security after Israeli attack.”

Trump also spoke on the phone later Wednesday to Qatar’s ruling emir, Sheikh Tamim bin Hamad Al Thani, according to a White House official who was not authorized to speak publicly and spoke on condition of anonymity.

The White House did not release details about the call, though Qatar later said the two men spoke about Doha's efforts to reach a ceasefire in the Israel-Hamas war.

The true scope of the pledge by the US remains in question. Typically, legally binding agreements, or treaties, need to receive the approval of the US Senate. However, presidents have entered international agreements without the Senate's approval, like President Barack Obama did with Iran's 2015 nuclear deal with world powers.

And ultimately, any decision to take military action rests with the president. That uncertainty has clouded previous US defense agreements in Trump's second term, like NATO's Article 5 guarantees.