Working with the Syrian army to fight the Islamic State group is not on the cards until President Bashar al-Assad has been removed from power, French Foreign Minister Laurent Fabius said Monday.

France's top diplomat said it was "obvious" Assad could not work alongside moderate rebels in Syria. 

Nearly 1,000 people thought to pose security risks have been denied entry into France since stepped-up border controls were imposed ahead of the COP21 climate talks on November 13, just hours before the Paris attacks, the interior minister said Saturday.

They were prevented from entering France "because of the risk these people could represent for public order and security in our country," Bernard Cazeneuve said during a visit to the northeastern city of Strasbourg.

Spain's government is stuck between a rock and a hard place.

Keen to show France support in its battle against extremism, Prime Minister Mariano Rajoy is also acutely aware that any concrete engagement will awaken the ghosts of Spain's devastating 2004 attacks just weeks ahead of general elections, experts say.

French Prime Minister Manuel Valls has called on the Gulf states to accept more refugees fleeing Syria, saying that a "humanitarian disaster" could erupt in the Balkans if Europe does not control its borders.

"I'll say it again, Europe cannot accept all the refugees coming from Syria. That's why we need a diplomatic, military and political solution in Syria," Valls said Friday evening.

President Francois Hollande vowed Friday that France would respond to the "army of fanatics" which carried out the Paris attacks with more songs, concerts and shows, as the nation paused to pay homage to the victims.

"We will not give in either to fear or to hate," said Hollande on a cold and misty day in the courtyard of the historic Invalides, the 17th-century complex housing Napoleon's tomb.

Four assault rifles used in the deadly Paris attacks were allegedly purchased from a trafficker in Germany, newspaper Bild reported Friday, as prosecutors said they were still probing a possible link.

Quoting documents from the Stuttgart prosecutor's office, the newspaper said two AK47s and two Zastava M70s were sold on November 7 by the arms dealer to a customer in Paris.

French Foreign Minister Laurent Fabius said Friday he could envisage Syrian regime troops taking part in the fight to crush the Islamic State group.

However, Fabius later clarified his comments, saying he meant that Syrian government troops could take part in the fight against IS only after a change of regime.

French President Francois Hollande and Russian leader Vladimir Putin agreed Thursday to coordinate strikes against Islamic State, but differences over Syria's future hampered efforts to bring Russia into a wider alliance to fight the jihadists.

Putin indicated France and Russia would swap data to help identify IS targets in Syria, as opposed to other groups opposed to the country's leader, Bashar Assad.

France's emergency services and military have seen a surge of interest from young people keen to join up after watching the Paris attacks unfold on television.

"During the attacks I saw all these emergency workers helping people voluntarily. I just felt powerless sitting in front of the TV and I said to myself that I wanted to help people as well," music student Simon Chaudemanche told AFP.

Germany will send up to 650 soldiers to Mali, Defense Minister Ursula von der Leyen said Wednesday, to provide some relief to France in its global fight against the Islamic State jihadists.

Von der Leyen made the announcement hours before German Chancellor Angela Merkel travels to Paris to meet President Francois Hollande to discuss support in the wake of the deadly November 13 attacks by the Islamic State group in the French capital.