TEHRAN, Iran (AP) — An Iranian-British woman long held in Tehran has been sentenced to another year in prison in Iran, her lawyer said Monday.

Nazanin Zaghari-Ratcliffe has already served a five-year prison sentence in the Islamic Republic.

Her lawyer, Hojjat Kermani, told The Associated Press that she received the second sentence on a charge of spreading “propaganda against the system” for participating in a protest in front of the Iranian Embassy in London in 2009.

State media in Iran did not immediately acknowledge the sentence. Her husband, Richard Ratcliffe, and the British Foreign Office did not immediately respond to requests for comment.

The latest twist in Zaghari-Ratcliffe’s case comes as Britain and Iran negotiate a long-running dispute over a debt of some 400 million pounds ($530 million) owed to Tehran by London. Before the 1979 Islamic Revolution, the late Iranian Shah Mohammad Reza Pahlavi paid the sum for Chieftain tanks that were never delivered.

She was sentenced to five years in prison after being convicted of plotting the overthrow of Iran’s government, a charge that she, her supporters and rights groups deny. While employed at the Thomson Reuters Foundation, the charitable arm of the news agency, she was taken into custody at the Tehran airport in April 2016 as she was returning home to Britain after visiting family.