U.S. President Donald Trump has signed an executive order pledging to guarantee Qatar's security, saying that any armed attack on the Gulf state will be considered a threat to the peace and security of the United States.

Qatar on Wednesday welcomed Trump's order, describing it as a milestone in strengthening defense ties and bilateral cooperation, its foreign ministry said.

The document was available Wednesday on the White House's website, but is dated on Monday, the day Trump hosted Israel's Prime Minister Benjamin Netanyahu at the White House and presented a proposal for ending the war in Gaza. Qatar has been a key mediator between the U.S. and Israel and Hamas over the war.

On September 9, Israel carried out air strikes on Doha, claiming they targeted senior Hamas leaders based in the city. Hamas said its delegation was in Doha at the time to discuss a U.S.-brokered ceasefire proposal. The strikes killed five Palestinians and one Qatari security officer, drawing widespread international condemnation.

The order highlights the long-standing cooperation between the two countries, noting that Qatar has hosted U.S. forces, enabled critical security operations, and acted as a steadfast ally in the pursuit of peace, stability and prosperity, including by mediating to help resolve regional and global conflicts.

Trump said in the order that it is the policy of the United States to ensure the security and territorial integrity of Qatar against external aggression, and that Washington would take "all lawful and appropriate measures – including diplomatic, economic and, if necessary, military – to defend the interests of the United States and the State of Qatar and to restore peace and stability."

(With input from agencies)