WASHINGTON - US President Barack Obama said Friday his government will "respond proportionally" to the cyber attack on Sony Pictures Entertainment (SPE), for which he pointed the finger at the Democratic People's Republic of Korea ( DPRK).

The attack "caused a lot of damage," Obama said during a year- end news conference at the White House. "We will respond proportionally, and we'll respond in a place and time and manner that we choose."

When asked if he is considering additional economic or financial sanctions on the DPRK, Obama said that his government has been "working up a range of options."

"I will make a decision on those based on what I believe is proportional and appropriate to the nature of this crime," he said.

Obama stressed that there is "no indication that North Korea was acting in conjunction with another country."

The attack in late November has prompted the US-based SPE to cancel the Christmas Day release of its comedy movie entitled "The Interview," which depicts an assassination attempt on DPRK leader Kim Jong Un. Obama called the SPE's decision "a mistake."

Early Friday, the US Federal Bureau of Investigation (FBI) claimed its investigation found what it called "enough information " to conclude that the DPRK was "responsible for" the attack, including linking the so-called data deletion malware used in this attack to "other malware that the FBI knows North Korean actors previously developed."

"There were similarities in specific lines of code, encryption algorithms, data deletion methods, and compromised networks," it said in a statement.

The bureau also cited "significant overlap between the infrastructure used in this attack and other malicious cyber activity the US government has previously linked directly to North Korea."

"Separately, the tools used in the SPE attack have similarities to a cyber attack in March of last year against South Korean banks and media outlets, which was carried out by North Korea," it said.

The DPRK has denied being behind the hack, saying such claims were "a wild rumor."

"The hacking into the SONY Pictures might be a righteous deed of the supporters and sympathizers with the DPRK," because the movie abets terrorism and hurts the dignity of the country's supreme leadership, a spokesman for the Policy Department of the National Defense Commission of the DPRK said earlier this month.