Poland's political standoff continues into fourth day

Polish Prime Minister Beata Szydlo and Jaroslaw Kaczynski attend a pro-government demonstration to mark the 35th anniversary of the marshal law in Warsaw, Poland, December 13, 2016. REUTERS/Kacper Pempel

WARSAW (Reuters) - Polish opposition lawmakers who accuse the ruling PiS party of undermining democracy and the constitution occupied the main hall of parliament for a fourth day on Monday, amid efforts to defuse Poland's biggest political standoff in years.

President Andrzej Duda was due to discuss the situation with the speaker of parliament and Law and Justice (PiS) party chief Jaroslaw Kaczynski. Duda, a PiS ally, met opposition leaders on Sunday.