Former National Security Adviser Michael Flynn has told associates that he spoke to Russia’s ambassador to the U.S. during the 2016 campaign about how the two countries could work together on key foreign policy matters if Donald Trump was elected, Mother Jones reported Thursday.

Two associates of the short-lived national security advisor told Mother Jones that Flynn’s contact with Sergey Kislyak predated the previously reported communications that the pair had during the post-election transition period.

One associate told the publication that Flynn and Kislyak proposed a situation in which Moscow would work with the Trump administration to end the Syrian civil war in exchange for an end to U.S. sanctions against Russia.

Another said Flynn spoke of talking to Kislyak about “Syria, Iran and other foreign policy matters” that the two countries could work together on if Trump took office.

These communications could be significant, given Russia’s active interference with the presidential election through the summer and fall of 2016. Only a sitting administration is supposed to negotiate policy issues with foreign governments.

Flynn pleaded guilty last December to lying to the FBI about his conversations about Russian sanctions with Kislyak during the transition. He has been cooperating with special counsel Robert Mueller over the past year, and is set to be sentenced on December 18.