Singapore, Jan. 18 -- The United States Senate formally began its impeachment trial of President Donald Trump on Thursday, as Chief Justice John Roberts was sworn in to preside over the proceedings and senators vowed to "do impartial justice" when deciding whether to remove him from office.

The two charges he faces - of abuse of power and obstruction of Congress regarding his conduct over Ukraine - were read out in the Senate at the start of what promises to be a divisive trial with a foregone conclusion: Mr Trump's acquittal, but along partisan lines.

The ceremonial beginning came amid more developments regarding Mr Trump's alleged pressure campaign against Ukraine to open an investigation into his political rival Joe Biden that would ...