TOKYO —Prime Minister Shinzo Abe strongly condemned acts of terror and pledged to support the United States Monday following a shooting massacre at a Florida nightclub overnight.

“We simply cannot forgive despicable acts of terror. We will continue to thoroughly advance efforts to wipe out terrorism,” Abe told reporters in Oita Prefecture in Japan’s southwest during a campaign stop for the upcoming House of Councillors election.

In remarks to the nation from the White House, President Barack Obama portrayed the carnage as the deadliest shooting in American history and an act of terror and hate.

“We must spare no effort to determine what, if any, inspiration or association this killer may have had with terrorist groups,” Obama said.

Some 50 people have been confirmed dead and 53 injured in the shooting at a gay club in Orlando in the southeastern U.S. state. U.S. authorities are investigating the incident as an act of terrorism.

Authorities said the gunman, who was killed by police, had expressed his allegiance to the Islamic State extremist group. The group has claimed responsibility for the attack on one of its affiliated websites. Still, it is unclear whether the shooter had any relation with the group.

“At this difficult time, Japan stands with the United States and its people,” Abe said in a message to U.S. President Barack Obama released the same day by the Japanese Foreign Ministry.

In his message, Abe expressed “great shock and strong anger” at the loss of life in the attack, offered condolences to the families of the dead and wished for a swift recovery for the injured.

“Terrorism is a challenge to the values Japan and the United States share,” Abe said.

“Sharing President Obama’s strong will to fight against terrorism, we will continue to engage in that fight together with the United States and global society,” he said.

Chief Cabinet Secretary Yoshihide Suga said Monday the government does not currently have information suggesting Japanese nationals are among the casualties, but is working to confirm the facts of the situation.

“The government will continue to devote itself to ensuring the safety of Japanese nationals in the United States,” Suga said.

© KYODO