Kuwait is investigating accounts that a drone violated its airspace and flew over the royal palace last Saturday
Kuwait's army said Wednesday it was raising its readiness levels and carrying out military exercises, amid soaring regional tensions after neighbouring Iran was accused of attacking Saudi oil infrastructure.
Kuwait also said it was investigating accounts that a drone intruded into its airspace and flew over the royal palace on Saturday, the same day an assault on two oil facilities knocked out half of Saudi Arabia's oil production.
"In view of the escalating situation in the country, the General Staff of the Army announces the lifting of the combat readiness of some of its units," it said in a statement posted on Twitter.
It said it was aiming to reach the "highest levels of readiness and combat efficiency" in order to "preserve the security of the country and the safety of its lands, waters and airspace from any potential dangers."
Yemen's Iran-allied Huthi rebels claim to have carried out Saturday's strike, but the United States has blamed Iran and there has been speculation the assault was launched from Iraq.
Saudi's defence ministry said Wednesday that the drones and cruise missiles struck from the north, ruling out Yemen as the source.
Iraq on Sunday denied any link, saying it is "constitutionally committed to preventing any use of its soil to attack its neighbours".
Kuwait shares land borders with Iraq and Saudi Arabia and sea borders with Iran.
Kuwait's Al-Rai newspaper said that at dawn on Saturday, an unmanned drone about the size of a small car came down to a height of about 250 metres over the palace, before turning on its lights and flying away.
It said the drone continued flew over the seaside residential palace of Emir Sheikh Sabah al-Ahmad Al-Sabah, who is undertaking medical tests in the United States.
Kuwait's government has already beefed up security measures around vital installations in the country.