"You can't get away with using proxy forces and think your homeland will be safe and secure.' We're going to respond against the actual decision-makers, the people who are causing this threat from the Islamic Republic of Iran".
European Union foreign policy chief Josep Borrell urged Iran's foreign minister by phone to work to de-escalate the situation and invited him to Brussels to discuss ways of preserving world powers' 2015 nuclear deal with Iran.
However, Iran has said it will continue to allow inspections by the International Atomic Energy Agency (IAEA) and is prepared to return to compliance with the deal if the U.S. removes sanctions.
US Secretary of State Mike Pompeo (R) shakes hands with German Foreign Minister Heiko Maas at the State Department in Washington, DC, on October 3, 2018.
The chilling announcement was broadcast live as millions of Iranians took to the streets for Soleimani's televised funeral.
Tensions have soared following the killing of top Iranian general Qassem Soleimani by a USA drone strike in Baghdad on Friday.
Iran said on Sunday it would abandon limitations on enriching uranium, taking a further step back from commitments to a 2015 nuclear deal with six major powers. "It is in everyone's interests that the deal remains in place", Mr Johnson's spokesman said.
Earlier on Sunday, the Ministry of Foreign Affairs confirmed that the head of business of the German embassy in Tehran had met with officials of the Ministry of Foreign Affairs of Iran, but did not provide details.
A regional political solution was the "only way forward", Borrell said, underlining "the importance of preserving" the 2015 Iran nuclear deal.
"Donald Trump's threat to destroy Iranian cultural sites would be a war crime under UN Security Council resolution 2347 - supported by the Trump Administration itself in 2017 to warn Daesh and Al Qaeda of similar actions".
And we're not allowed to touch their cultural sites?
German Foreign Minister Heiko Maas called on Sunday for a crisis meeting of his European Union counterparts this week to discuss escalating tension in the Middle East following the killing of a top Iranian military commander in Iraq by the United States.
"I find it hard to believe the Pentagon would provide Trump targeting options that include Iranian cultural sites", said Colin Kahl who was National Security Adviser to former vice president Joe Biden.
Iran's Supreme National Security Council Secretary Ali Shamkhani told state television the Iraqi parliament's vote means the US military presence in Iraq is considered an occupation.