Condolences poured in from across the globe as France reeled under a series of devastating attacks that left at least 150 people dead. World leaders, including Iranian President Hassan Rouhani and U.S. President Barack Obama, were unanimous in their condemnation of the deadliest violence to strike France since World War II.

"The death of many civilians in the terrorist attacks causes deep grief to the Iranian people," Rouhani said, according to the state-run IRNA news agency.

The Iranian leader, who was scheduled to begin his trip to Italy and France Saturday, also postponed the event.

"It is better now to focus on fighting terrorism and President Rouhani's trip to Europe will happen in near future," Iran's foreign minister, Mohammad Javad Zarif, reportedly said.

Several other Persian Gulf nations, including Saudi Arabia, the United Arab Emirates, Kuwait and Qatar also denounced the attacks in similar terms, calling them "criminal acts of terrorism which run counter to all teachings of the holy faith and humanitarian values."

Turkey, the host of the upcoming G20 summit, also spoke out against the attacks, with President Recep Tayyip Erdogan vowing to continue his "resolute stance against terrorism."

Until now, no group has claimed responsibility for Friday night’s attacks that targeted restaurants, a concert hall and a sports stadium at locations across Paris. A total of eight attackers are believed to have been killed.

"We're going to do whatever it takes to work with the French people and nations around the world to bring these terrorists to justice and to go after any terrorist networks that go after our people," Obama said, in a statement released late Friday.

In other parts of the world, nations that have been, in the past, targeted by terrorism, joined in to condemn the violence, described by the United Nations as "barbaric and cowardly."

In London, where over 50 people were killed in a terrorist attack 10 years ago, British Prime Minister David Cameron said he and his government will "do whatever we can to help."

German Chancellor Angela Merkel said she was "deeply shocked" by the attacks, while Jose Manuel Garcia Margallo, the foreign minister of Spain, warned of a possible repeat attacks.

"All of this confirms that we are facing an unprecedented challenge, a hugely cruel challenge," Margallo told the Spanish public television TVE.

Russian President Vladimir Putin and Chinese President Xi Jinping also joined Obama and other world leaders in expressing their condemnation of the "horrible terrorist attacks." The Russian leader sent his condolences to the French people in a statement published by the Kremlin.

"Russia strongly condemns this inhumane killing and is ready to provide any and all assistance to investigate these terrorist crimes," Putin said.

In a message to his French counterpart, Xi said: "At the sorrowful moment of the French people, I, on behalf of the Chinese government and the Chinese people, and personally, condemn in the strongest terms the barbaric acts."

The Vatican, meanwhile, expressed shock at the "new manifestation of maddening, terrorist violence" and called for "decisive, supportive response" to end the spread of "homicidal hatred."