British police carried out an overnight raid on a house in Birmingham that police say is linked to yesterday's deadly terrorist attack in London outside the Palace of Westminster that left five people dead and forty more injured.

While officials say the attacker has likely been identified, they are not prepared to name him or his potential associates other than to say they are considering the attack as an incident of Islamic-inspired terrorism.

Scotland Yard said Thursday that their investigation would continue to focus on the attacker's "motivation and preparation" and that six addresses around the country had been searched and the seven others had been arrested. 

Britain's Houses of Parliament, which sits inside the Palace of Westminster, will open as usual Thursday, lawmakers have said, following a defiant statement last night from Prime Minister Theresa May. 

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"The location of this attack was no accident. The terrorists chose to strike at the heart of our capital city, where people of all nationalities, religions and cultures come together to celebrate the values of liberty, democracy and freedom of speech," May said in a nationally-televised address. "These streets of Westminster - home to the world's oldest parliament - are ingrained with a spirit of freedom that echoes in some of the furthest corners of the globe."

May is also due to address lawmakers later Thursday in the House, which remains under heavy police and security services protection following Thursday's attack.

Police have also confirmed that name of the officer murdered in yesterday's attack as 48-year old PC Keith Palmer, who died after receiving multiple stab wounds from the attacker, who appears to have driven his car at speed along Westminster Bridge, which runs adjacent to Parliament, striking several pedestrians -- two of whom later died -- before lunging at PC Palmer with two large knives.

Five people -- including the alleged attacker -- are said to have died in the attack and forty more were injured, some of them gravely, after being struck by the speeding 

Westminster Bridge -- a busy connection point between north and south London across the River Thames -- remains closed Thursday as police continue the investigation amid what Scotland Yard has described as "large and complicated crime scene" while the city and the country remain on high alert.