US President Donald Trump on Tuesday marked Christmas with a renewed attack on the central bank over plunging stocks, as he aired a catalogue of grievances in a downbeat gathering at the Oval Office. High on the laundry list was the Democrats, whom he blamed for a partial government shutdown which dragged into its fourth day — paralyzing key federal services such as national parks — with no end in sight. With the stock market on track for its worst December since the Great Depression, Trump berated the Federal Reserve for its stewardship of the economy, a regular recent complaint.