Masahiko Komura, the ruling Liberal Democratic Party's vice president, said Wednesday that Japan will not comply with the Islamic State's ransom demand, after the militant group threatened to kill two Japanese it is holding hostage.

"Withdrawal of the humanitarian support is out of the question," Komura told reporters at LDP headquarters. "It means (the government) cannot comply with the demand for ransom.

"I believe the government should do the best to save the hostages' lives," Komura said.

In a video purportedly released by the Jihadi group, a militant wielding a knife issues a demand for $200,000 because Prime Minister Abe "has proudly donated $100 million to kill our women and children and destroy the home of Muslims."

The man also said that Abe donated another $100 million "in an attempt to stop the expansion of the Islamic State."

Meanwhile, during a round of talks between LDP Secretary-General Sadakazu Tanigaki and his Komeito counterpart, Yoshihisa Inoue, in Tokyo, the two ruling parties agreed to back the Abe government's stance.

Both agreed to cooperate with representatives of the LDP and, if necessary, to attend further talks in order to respond to the hostage crisis.