"President Trump pledged the full cooperation and support of the United States Government in responding to the attack and bringing those responsible to justice," the White House said in a readout of the call.
During the call, Trump praised the effective response of British security forces.
"We obviously condemn today's attack in Westminster, which the United Kingdom is treating as an act of terrorism and we applaud the quick response that the British police and their first responders made to the situation," White House press secretary Sean Spicer said at his daily press briefing. US Secretary of State Rex Tillerson condemned the terror attack at the British Parliament in London describing it as horrific act of violence.
"On behalf of the US, I express my condolences to the victims and their families. The American people send their thoughts and prayers to the people of the United Kingdom," he said.
The Department of Homeland Security said it stands in solidarity alongside its friends in the United Kingdom in condemning the terrible attack at Parliament.
"With our partners in federal law enforcement, we are in close contact with our British counterparts to monitor the tragic events and to support the ongoing investigation. At this time our domestic security posture remains unchanged," the statement said.
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