WASHINGTON, Oct. 31 (Xinhua) -- U.S. President Donald Trump on Tuesday vowed to defeat the Islamic State group after a terrorist attack in New York killed eight people.

"In NYC, looks like another attack by a very sick and deranged person. Law enforcement is following closely," he tweeted.

"We must not allow ISIS to return, or enter, our country after defeating them in the Middle East and elsewhere, Enough!" he added.

Trump also offered his "thoughts, condolences and prayers to the victims and families" of the the attack.

A man driving a rented pickup truck plowed into pedestrians near the World Trade Center in New York City on Tuesday afternoon, killing eight people and wounding dozens, police said.

Describing it a terrorist attack, Trump vowed to clamp down on the Islamic State, an extremist group that was born in the Middle East and has carried out deadly attacks in America and Europe in recent years.

U.S. State Department Spokeswoman Heather Nauert said Tuesday that the State Department is closely monitoring the situation.

"We extend our condolences to the families of the victims and our prayers for recovery to those affected by this terrible act of terrorism in New York City," said Nauert in a statement.

U.S. Vice President Mike Pence said "the U.S. people stand with NYC after today's cowardly act of terror. When terrorist bring violence, America always brings justice and resolve."

The U.S. Department of Homeland Security (DHS) said it is committed to "safeguarding" the country in face of terrorist attacks.

"We have recently seen attacks like this one throughout the world. DHS and its law enforcement partners remain vigilant and committed to safeguarding the American people," it said in a statement.

Nancy Pelosi, the minority leader in the House of Representatives, called the attack a "despicable act of terror in Manhattan," and urged fellow politicians to be "not reckless and rash."