President Donald Trump said Monday that the ceasefire with Iran is “on life support” after Iran’s response to the latest U.S. peace proposal. He has rejected Iran’s reply as “totally unacceptable” and on Monday called it a “piece of garbage.”

The Iranian government insists it demanded only the country’s “legitimate rights” and no “concessions” in its response.

Trump is expected to encourage China to pressure Iran into making a deal to end the costly war during his visit to Beijing later this week, when he will meet with President Xi Jinping.

Speaker of Iran’s parliament said his country’s military stood ready to “teach a lesson” to any aggressor on Monday, after President Trump warned the ceasefire in the Middle East was hanging by a thread.

“Our armed forces are ready to respond and teach a lesson for any aggression,” Mohammad Bagher Ghalibaf said on social media.

“A bad strategy and bad decisions always lead to bad results — the world already understands this.”