Checkout The Heart Breaking Pictures Of Paris Terrorist Attack 2015.

Gunmen and bombers attacked busy restaurants, bars and a concert hall at locations around Paris on Friday, killing nearly 140 people in what a shaken President Francois Hollande described as an unprecedented terrorist attack.

The apparently coordinated gun and bomb assault came as the country, a founder member of the US-led coalition waging air strikes against Islamic State fighters in Syria and Iraq, was on high alert for terrorist attacks ahead of a global climate conference due to open later this month.

Hollande, who was attending an international soccer match with German Foreign Minister Frank-Walter Steinmeier when several explosions took place outside the national stadium, declared a state of emergency in the Paris region and announced the closure of France's borders to stop perpetrators escaping.

"This is a horror," the visibly shaken president said in a midnight television address to the nation before chairing an emergency cabinet meeting.

All emergency services were mobilised, police leave was cancelled and hospitals recalled staff to cope with the casualties.

UN Secretary-General Ban Ki-moon condemned "the despicable terrorist attacks carried out today in various locations in and around Paris," and demanded "the immediate release of the numerous individuals reportedly being held hostage in the Bataclan theater," said a statement issued by Ban's spokesman.

"The secretary-general trusts that the French authorities will do all in their power to bring the perpetrators to justice quickly," said the statement.

A hostage situation is continuing at a concert hall in the French capital, reports said, adding that police believe terrorists are holding 100 hostages inside the venue.

French President Francois Hollande, evacuated from Stade de France, is in the Interior Ministry for an emergency meeting with Interior Minister Bernard Cazeneuve.

Hollande announced on Friday night that emergency state across France is declared and France will close its borders. He also said that "unprecedented terrorist attacks are ongoing in Paris."

British Prime Minister David Cameron on Friday said he was "deeply shocked" by the deadly attacks in Paris, offering "thoughts and prayers" to the French people.

"I am shocked by events in Paris tonight. Our thoughts and prayers are with the French people. We will do whatever we can to help," Cameron said via his Twitter account.

German Chancellor Angela Merkel said on Friday evening that she was deeply shocked by the attacks in Paris and declared solidarity with France.

"I was deeply shocked by the news and images that we have got from Paris. My thoughts are in these hours with the victims of the attacks, their families, and all people in Paris," said Merkel in a statement.

US President Barack Obama on Friday condemned the deadly attacks currently still unfolding in Paris and said it was too early to determine who was behind those attacks.

Calling the attacks in and around Paris on Friday evening "an outrageous attempt to terrorize innocent civilians," Obama said the US stood ready to provide assistance for the French government.

He also said US officials were "in contact with French counterparts to communicate condolences to families of the victims".