US Secretary of State John Kerry has
described Islamic State (IS) militants as "psychopathic monsters"
following Friday's deadly attacks in Paris.
Mr Kerry, in Paris for talks with President Hollande, said the US stood "shoulder to shoulder" with France.Mr Hollande says France is committed to destroying IS. French air strikes hit the militants in Syria overnight.
IS has said it carried out the attacks on bars, restaurants, a concert hall and a stadium in which 129 people died.
A huge manhunt is still under way for a suspected member of the group, Salah Abdeslam, who was believed to have fled across the border to his native Belgium.
Latest updates
Interior Minister Bernard Cazeneuve told France Info TV that 128 raids on suspected Islamist militants had been carried out overnight on Monday to Tuesday. More than 160 raids were made earlier on Monday, with 23 people arrested and dozens of weapons seized.
Belgium's government has raised its terror threat level, causing Tuesday's football match between the national team and Spain to be cancelled.
The BBC's Barbara Plett Usher, who is travelling with Mr Kerry, says his visit to Paris is to demonstrate Washington's support for a key ally.
In the wake of the attacks, the two countries have tightened their military co-operation, boosting the exchange of intelligence to help French air strikes against IS.
Meanwhile early on Tuesday, French warplanes carried out fresh strikes against the IS stronghold of Raqqa in northern Syria, the army general staff said, destroying a command centre and training centre.
More on the Paris attacks
- What happened in Paris? How events unfurled on Friday evening in the French capital.
- Who were the victims? Details of some of the 129 people killed in the attacks.
- The fight against Islamic State at home and abroad The attacks have highlighted once again the difficulties in providing total security in a modern, open Western capital.
- Most wanted: Alleged mastermind Profile of key suspect Abdelhamid Abaaoud, thought to be behind the attacks and now based in Syria.
- Anonymous 'declares war' on Islamic State The hacking group vows to use its knowledge to "unite humanity" and "hunt down" IS members.
Standing outside the US embassy on Monday, Mr Kerry called France America's oldest friend and first ally, and said the only response to the attacks must be a fierce sense of solidarity.
"Your American sisters and brothers will stand with you shoulder to shoulder as we have stood together throughout history. Tonight we are all Parisians," he said.
Mr Kerry added that the fight against IS was not a clash of civilisations.
"They are in fact psychopathic monsters. There's nothing civilised about them," he said.
After he spoke the building was illuminated in the blue, white and red of the French flag.
State of emergency
The attacks in Paris - which also left more than 400 people wounded, some critically - have galvanised Western countries in their campaign against the so-called Islamic State.UK Chancellor George Osborne is due to say in a speech on Tuesday that IS is trying to develop the ability to launch deadly cyber-attacks on the UK.
During a visit to the GCHQ listening station in Cheltenham, he is to announce that the UK's investment in fighting cybercrime will double.
Prime Minister David Cameron has already announced extra funding for UK special forces, such as the elite SAS, following Friday's attacks.
President Hollande told a rare joint session of the French parliament on Monday that he would table a bill to extend for three months the state of emergency declared after the attacks. He said thousands more police officers would be recruited.
Seven people were detained in Belgium over the weekend, two of whom were charged on Monday with "participating in a terrorist attack".
The other five were later released, including Mohammed Abdeslam, the brother of two suspects - Brahim Abdeslam, killed during the attacks, and Salah Abdeslam.
Suspected Paris attackers
- Salah Abdeslam, 26 - urgently sought by police
- Brahim Abdeslam, 31 - named as attacker who died near Bataclan concert hall
- Omar Ismail Mostefai, 29, from near Paris - died in attack on Bataclan
- Bilal Hadfi, 20 - named as attacker who died at Stade de France
- Ahmad al-Mohammad, 25, from Idlib, Syria - died at Stade de France (unverified)
- Samy Amimour, 28, from near Paris - suicide bomber at Bataclan
Authorities say that one of the attackers was the same man who used a Syrian passport in the name of Ahmad al-Mohammad and whose fingerprints match those taken by the Greek authorities after he arrived with migrants on the island of Leros in October.
As well as the attackers themselves, investigators are also reported to be focusing on a Belgian of Moroccan descent who is described as the possible mastermind of the attacks.
Abdelhamid Abaoud, 27, lived in the Molenbeek neighbourhood of Brussels, as did two of the attackers, and is now believed to be based in Syria, where he has risen through the ranks of IS.