A U.S.-led bloc of Arab nations took aim at the nexus between Iran and the Taliban on Tuesday, as part of a sanctions crackdown against the backdrop of violence in Afghanistan and a diplomatic crisis with Saudi Arabia.

“The United States and our partners will not tolerate the Iranian regime exploiting Afghanistan to further their destabilizing behavior,” Treasury Secretary Steven Mnuchin said in remarks accompanying the bulletin.

Mnuchin made the announcement from Riyadh, the same city in which President Trump signed an agreement to establish the Terrorist Financing Targeting Center — a group of the six members of the Gulf Cooperation Council and the United States. The U.S. and Arab leaders blacklisted nine Iranian and Afghan individuals who have worked in various ways to foster cooperation between the Shia mullahs and the Taliban.

“Iran’s provision of military training, financing, and weapons to the Taliban is yet another example of Tehran’s blatant regional meddling and support for terrorism,” Mnuchin said. “We are also targeting key Iranian sponsors providing financial and material support to the Taliban.”

The announcement comes on the heels of an insider attack in Kandahar, Afghanistan, at which two senior American generals were present. Brig. Gen. Jeffrey Smiley was wounded in the shooting, according to reports, but Army Gen. Scott Miller — the top commander of U.S. and NATO forces in the country — was unharmed. U.S. officials have accused Iran of "propping up the terrorist networks that are killing innocent people” this year.

“Russia is not helping at all. ... Iran is not helping at all,” Kay Bailey Hutchison, the U.S. ambassador to NATO, said in April. “We hear this when we’re in Afghanistan, and we hear from the military leaders. They talk about the enablers — those who have the money and the capacity to be helpful, but instead are really propping up the terrorist networks that are killing innocent people.”

The insider attacks, paired with the sanctions announcement, highlights the cross-pressures that are shaping U.S. relations with allies in the Middle East. Mnuchin attended the TFTC meeting, but he canceled a trip to a major economic forum hosted by Saudi Arabia, as part of the fallout over the murder of Saudi dissident and Washington Post columnist Jamal Khashoggi.

That killing has even outraged lawmakers who traditionally support close ties with the oil-rich monarchy, straining Trump’s efforts to deepen cooperation with Saudi Arabia against Iran. Likewise, the sanctions announcement united Saudi Arabia and Qatar under one banner, despite an ongoing diplomatic breach within the Gulf Cooperation Council that involves a Saudi blockade of their Qatari neighbors.

“The TFTC has again demonstrated its tremendous value to international security by disrupting and exposing key Taliban members who are involved in suicide attacks, and other lethal activities,” Mnuchin said.