Speaking in Paris, US Secretary of State John Kerry has pledged support for France and vowed to defeat the "Islamic State." Authorities in Belgium are continuing their hunt for the main suspect behind Friday's attacks.
Speaking before the US embassy in Paris, which was illuminated in the colors of the French flag late on Monday, Kerry said the US and France were "not only friends," but family.
"We will defeat Daesh and all who share their despicable ideology, and we will continue to show compassion to those who seek refuge from the violence the terrorists engender," Kerry said, using another name for the so-called "Islamic State" (IS).
"We will fight to ensure the world our children inherit is rich in love and short on hate," he added.
Kerry's comments came hours after IS posted a new video online in which they vowed to attack every country involved in bombing Syria, claiming that the US capital, Washington DC, would be the next target.
Ahead of his meeting with French President Francois Hollande and Foreign Minister Laurent Fabius on Tuesday, Kerry also described the jihadi militants, who killed 129 people and injured more than 350 in Paris last Friday, as "psychopathic monsters."
Last week's attacks will not change US President Barack Obama's plans to attend a global climate summit in Paris at the end of the month, however.
France and the US reaffirmed their military cooperation over the weekend, with Obama saying that a new agreement had been forged on intelligence-sharing for airstrikes in Syria.
US Defense Secretary Ash Carter said on Monday that the US military was "looking for opportunities to get at IS, adding that the methods included airstrikes on oil infrastructure and identifying and aiding effective ground forces against the militants.
Carter criticized Europe's efforts, however, saying that America's European allies were not spending enough on defense.
Manhunt continues for alleged mastermind
Speaking at a rare joint session of parliament on Monday, Hollande declared that "France is at war" with the "Islamic State," which has claimed responsibility for Friday's attacks.
The president told IS militants that "the French republic has overcome other obstacles."
Over the weekend searches were carried out and multiple people were arrested in the Brussels district of Molenbeek
"Those who attempted anything against us in history have lost," Hollande warned.
Meanwhile, officials in Belgium are continuing their manhunt for Salah Abdeslam, a 26-year-old Frenchman based in Brussels who is said to have helped organize the attacks. Abdelhamid Abaaoud, a 27-year-old Belgian man who was identified by French investigators as the mastermind behind the attacks, had been previously linked to several other abortive shooting plots in Belgium and France.
Amid security concerns, the Belgian football federation has also called off its friendly match against Spain scheduled for Tuesday evening. Germany is still set to host the Netherlands in Hanover, and the French national team will play against England in London in their first outing since the attacks.
ksb/cmk (Reuters, AFP, AP, dpa)