WASHINGTON (Reuters) - U.S. Secretary of State Antony Blinken said on Wednesday he would personally convene world foreign ministers before the end of the year to follow up on commitments made toward fighting the coronavirus pandemic.

       At a virtual COVID-19 summit on the sidelines of the UN General Assembly, President Joe Biden earlier promised to buy 500 million more COVID-19 vaccine doses to donate to other countries as the United States comes under increasing pressure to share its supply with the rest of the world.

       Blinken said he would convene foreign ministers to follow up on commitments made at the virtual summit and at an upcoming G20 meeting, ahead of a meeting of heads of state led by Biden to be held in the first quarter of 2022.

       "We have to have the sustained engagement, continuing to hold ourselves accountable, for real progress," Blinken said.

       (Reporting by Simon Lewis and Humeyra Pamuk; Editing by Steve Orlofsky)