Iran on Thursday warned of a "proportionate and firm" response after Germany said the European Union was seeking to adopt new sanctions against it over a deadly crackdown on protests.
"Provocative, interventionist and undiplomatic stances don't signal sophistication and wisdom," Iranian Foreign Minister Hossein Amir-Abdollahian tweeted.
"Undermining old ties has long-term consequences. Germany can choose engagement to address shared challenges -- or confrontation. Our response will be proportionate and firm," he added, without elaborating.
Germany's Foreign Minister Annalena Baerbock said on Wednesday that the European Union was "working flat out on the next package of sanctions" against Iran in response to its crackdown on the protests ignited by Mahsa Amini's death.
"We won't let up," she tweeted. "We stand with the men and women of Iran, not only today, but as long as it is necessary."
EU foreign ministers are due to meet in Brussels on Monday.
The 27-nation bloc had already imposed sanctions in mid-October against Iran's "morality police" and 11 officials including the telecommunications minister.
Amini died in the custody of the morality police on September 16, three days after falling into a coma following her arrest in Tehran for allegedly breaching the Islamic republic's hijab dress rules for women.
Dozens of people, mainly protesters but also members of the security forces, have been killed since the start of the protests.
Thousands more have been arrested during the demonstrations, generally referred to as "riots" by the authorities.