The United Nations General Assembly on Friday adopted a $3.07 billion operating budget which for the first time includes funding for the investigation of war crimes in Syria and Myanmar.

The budget represents a slight increase from 2019's figure of $2.9 billion.

The increase is due to additional missions assigned to the UN Secretariat, inflation and exchange rate adjustments, according to diplomats.

These include the observer mission in Yemen, a political mission established in Haiti, the investigation of crimes committed in Syria since the outbreak of civil war in 2011, and in Myanmar after the 2017 crackdown on the Rohingya Muslim minority.

For the first time, the budgets for the Syria and Myanmar investigations -- which were previously financed by voluntary contributions -- will in 2020 be transferred to the UN secretariat's budget and will receive compulsory contributions from the 193 member states.

Russia proposed multiple amendments during negotiations in the Committee on Budgetary Questions meeting and in the General Assembly plenary session.

At each vote, Russia, Syria, Myanmar and their supporters, including North Korea, Iran, Nicaragua and Venezuela, were outvoted. They all stated that they dissociated themselves from references to investigative mechanisms in the adopted resolutions.

Russia said it would examine its future obligatory payments in light of the vote outcome and predicted an increase in the arrears that currently plague the UN's treasury due to countries not paying enough.

Moscow argued Friday the investigative mechanism was illegitimate, while Damascus stressed that it had no mandate from the Security Council.

The UN's operating budget is separate from the annual budget for peacekeeping operations of some $6 billion that is adopted in June.