Sunday night, President Trump set the tone, saying America was “locked and loaded” but waiting to hear from Saudi Arabia about who they believe was responsible for the attack on an oil refinery.

This morning Saudi Arabia announced that the weapons used in the attack were Iranian though the place where the weapons were launched remains unclear. From the Washington Post:

Saudi Arabia charged Monday that Iranian weapons were used to attack the kingdom’s oil installations, dismissing claims of responsibility by Yemen’s Houthi rebels, who threatened additional assaults amid U.S. warnings of retaliation…

A Saudi military spokesman said Monday that a preliminary investigation found that the weapons used against the facilities were Iranian.

In a televised briefing, Col. Turki al-Malki, a spokesman for a Saudi-led coalition in Yemen, also said the attacks did not originate in Yemen and that investigations were underway to determine the launch location…

U.S. officials are working under the assumption that the strikes did not emanate from Yemen and do not believe they were launched from Iran, either, said the official, who is familiar with ongoing discussions about the attacks but was not authorized to speak publicly.

While the Post is reporting that U.S. officials don’t believe the attack came from Iran, the NY Times reported yesterday that satellite photos show the attacks came from the north, i.e. in the direction of Iran, not the direction of Yemen.

The government released satellite photographs showing what officials said were at least 17 points of impact at several Saudi energy facilities from strikes they said came from the north or northwest. That would be consistent with an attack coming from the direction of the northern Persian Gulf, Iran or Iraq, rather than from Yemen, where the Iranian-backed Houthi militia that claimed responsibility for the strikes operates.

Administration officials, in a background briefing for reporters as well as in separate interviews on Sunday, also said a combination of drones and cruise missiles — “both and a lot of them,” as one senior United States official put it — might have been used. That would indicate a degree of scope, precision and sophistication beyond the ability of the Houthi rebels alone.

This morning President Trump suggested Iran might be lying when it claims it has no involvement:

The attack on an Aramco refinery is expected to cut Saudi oil production in half for the near future. That represents a loss of about 5 percent of the world’s daily oil supply. Crude oil prices jumped 20 percent in early trading this morning but settled at around 10 percent over last week’s level.

Houthi rebels in Yemen, who claimed responsibility for the initial attack, threatened additional attacks this morning. The Houthis are supported and armed by Iran. Iran has, of course, denied any involvement in the attack. Both Russian and China are warning against a rush to judgment.