LONDON (AP) — Britain says Foreign Secretary Boris Johnson has spoken to the husband of a British woman imprisoned in Iran as pressure mounts on the Conservative government to step up efforts to free her.

The Foreign Office says Johnson and Richard Ratcliffe spoke by phone Sunday, but did not elaborate further.

Dual U.K.-Iranian citizen Nazanin Zaghari-Ratcliffe is serving a five-year sentence for plotting the "soft toppling" of Iran's government.

Earlier this month, Johnson told lawmakers that Zaghari-Ratcliffe was "teaching people journalism" when she was detained last year. Her family and employer insist she was simply visiting her family.

On Sunday, Environment Secretary Michael Gove said "I don't know" when asked what Zaghari-Ratcliffe was doing in Iran.

Family and friends say the confusion has put Zaghari-Ratcliffe at risk of a longer prison sentence.