Mr Trump said the 2015 agreement, which included Germany, France and Britain, was a "horrible one-sided deal that should never ever have been made".
He added that the United States "will be instituting the highest level of economic sanction".
Pastor Sam Yeghnazar from 222 Ministries told Premier he has big concerns for the people of Iran following the announcement, especially Christians who are seen as a minority and often face persecution.
"There might be more brutality, there might be killing and bloodshed, " he said. "The consequences of this decision - right or wrong - will be catastrophic for the Iranian society including the Christians."
Officials from France, Britain and Germany will meet Iranian representatives next week.
They're going to try to keep the agreement together, which aims to prevent Iran making an atomic bomb.
Pastor Sam Yeghnazar called on believers in the UK to pray for wisdom and restraint for leaders both in Iran and the West.
He also claimed we may be seeing a Bible story repeating itself in Iran.
"We see the story of Pharaoh of how God hardened his heart.
"Is it possible that God is hardening the heart of the Iranian leaders so that in their despotic rule people will turn to God?"
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