WASHINGTON, Nov 29 (Reuters) - Walmart has seen a 26% increase in shipping containers going thru clogged United States ports over the past four weeks, chief executive Doug McMillon said at the White House on Monday, ahead of a meeting with President Joe Biden on supply chain issues.

In Southern California, container movement has jumped 51%, he said.

"We are seeing progress. The port and transit delays are improving," McMillon told Biden during the meeting with CEOs. (Reporting by Alex Alper, Editing by Nick Zieminski and Sonya Hepinstall)