"The Department of Homeland Security is closely monitoring the attack near a mosque in London in addition to early reports of the attack in Paris this morning," the statement said.
Secretary John Kelly has been briefed on both incidents.
The department said it stands with the European nations in fighting terrorism, and will work to keep "our communities safe against violent extremists who target any of our people."
One person died overnight in London after a man drove a white van into a crowd of congregants leaving a mosque, injuring 10 people. Worshippers restrained the 47-year old assailant and police took him into custody.
Earlier Monday, another man drove a vehicle into a police car in Paris, exploding the vehicle. No one was injured in the attack and police confirmed the attacker died.