<span style="color: #222222;">United States President Donald Trump has warned Iran of significant retaliation if Americans are killed or its facilities damaged in attacks by the Islamic Republic.<br />''<br />''Trump wrote on Twitter yesterday, that they will pay a very big price. This was not a warning, but a threat, he said, after pro-Iranian protesters stormed the US Embassy in Baghdad.<br />''<br />''Meanwhile, Mr Trump thanked Iraqi Prime Minister Adel Abdel Mahdi and President Barham Saleh for their rapid response upon request to the embassy attack, said the White House.</span><br />