A deluge of sanctions may be imposed on Turkey as a US delegation including Vice President Mike Pence and Secretary of State Mike Pompeo sets off for Ankara to negotiate a cease-fire in Syria with Turkish President Recep Tayyip Erdogan and other top officials.

Last week, US President Donald Trump gave the green light for a Turkish military operation in northeast Syria, where Ankara seeks to create a buffer zone between its border and US-backed Kurdish militants it views as security threat. The ongoing fighting has brought international condemnation as well as resistance within Washington, and now the Trump administration appears to be reversing course by threatening to impose severe sanctions if Turkey does not pull back its troops.

Following initial approval of the incursion, Trump introduced a sanctions package Monday targeting Turkish steel exports, trade talks and a number of Ankara officials. Yet built-up anger in Washington over an array of Turkish policies and actions in recent years appears to be driving a push for more severe reprisals on Ankara.

Republican Senator Lindsey Graham stated he would introduce a bill Thursday with bipartisan support that could unroll the Countering America’s Adversaries Through Sanction Act (CAATSA), which has so far been deferred following Ankara’s acquisition of the Russian-made S-400 missile defense system this summer, and would potentially hinder Turkey’s defense and energy sectors. On Wednesday, members of the US House of Representatives also said they would seek to impose sanctions through a separate piece of legislation.