Police said fake blood and a pig’s head were left outside the California home of Nancy Pelosi, the Democratic Speaker of the House of Representatives.
In Kentucky, graffiti was scrawled on the house of Senate Majority Leader Mitch McConnell, a Republican.
Congress is deadlocked over a relief package for the coronavirus pandemic.
On Tuesday the House voted to increase the one-off payments sent to individuals from $600 (£440) to $2,000. The Democratic-controlled chamber passed the bill with the help of more than 40 Republicans.
But the Republican-led Senate has not approved the bigger cheques, despite calls to do so from US President Donald Trump.
The two houses of Congress will convene for a new session, with recently elected lawmakers to be sworn in.
Ms Pelosi will be re-elected as House speaker, but with a reduced majority, after the Democrats lost seats in the 3 November election.
Mr McConnell remains as Senate majority leader but could be unseated if the Democrats win special elections for both Senate seats in Georgia on Tuesday.
Source : BBC News
