(Changes dateline to United Nations, adds detail throughout)
By Michelle Nichols
UNITED NATIONS, Feb 12 (Reuters) - The United Nations Security Council on Thursday banned all trade in antiquities from war-torn Syria, threatened sanctions on anyone buying oil from Islamic State and al Qaeda-linked Nusra Front militants and urged states to stop kidnap ransom payments.
The 15-nation council unanimously adopted a Russian-drafted resolution, which is legally binding and gives the council authority to enforce decisions with economic sanctions. It does not authorize using military force.
U.S. Ambassador to the United Nations, Samantha Power, lamented that the council had not been able to show the same unity on attempting to bring an end to the four-year civil war in Syria, blaming the conflict for the rise of Islamic State.
"Just as we condemn the monstrosities perpetrated by (Islamic State) we must also continue to condemn the brutality of (Syrian President Bashar al-Assad's) regime, which has long since lost the legitimacy to lead," Power told the council.
She rejected claims that the United States needed to partner with the Syrian government to confront violent extremists.
The U.N. Security Council has long been deadlocked on Syria with Assad's ally Russia, backed by China, vetoing several resolutions on the Syrian conflict.
The resolution on Thursday banned trade in Syria antiquities and reaffirmed a ban on Iraqi artifact sales from about a decade ago.
It expressed concern that Islamic State and others "are generating income from engaging directly or indirectly in the looting and smuggling of cultural heritage items ... to support their recruitment efforts and strengthen their operational capability to organize and carry out terrorist attacks."
According to a U.N. report in November, it was very difficult to estimate how much money Islamic State was generating from the looting and trade in Syrian and Iraqi antiquities.
The resolution builds on previous efforts to target Islamic State oil sales. It urges states to stop vehicles leaving or entering Islamic State and Nusra Front territory that could be smuggling oil, metals, grain, livestock, electronics, and cigarettes for international sale or to barter for weapons.
In November the U.N. estimated Islamic State's revenue from oil ranged between $846,000 to $1.6 million a day. However, the Pentagon has assessed that oil was no longer the main source of revenue for Islamic State. Western diplomats have said this was due to air strikes on oil installations and a plunge in oil prices that has affected black market prices as well.
The U.N. report said Islamic State was raising about $96,000 to $123,000 per day from ransom payments. The resolution calls upon "all Member States to prevent terrorists from benefiting directly or indirectly from ransom payments or from political concessions and to secure the safe release of hostages."
Reporting by Michelle Nichols; Editing by Chizu Nomiyama and Tom Brown