Sunday was another fruitless day in the search for the missing Malaysian passenger jet.

Searchers on nine planes and eight ships scoured a large swath of the Indian Ocean west of Australia and again found some debris floating on the surface. But Australian authorities said it turned out to be "fishing equipment and other flotsam."

The search for the missing Boeing 777 jet is in its fourth week, but searchers have yet to identify any ocean-borne debris as connected to the aircraft.

More ships are on the way to the search area, including an Australian naval vessel, the Ocean Shield, which is equipped with sophisticated U.S. equipment to try to detect pings from the plane's data recorder. It will take a few days for the Ocean Shield to arrive at the location where officials say Flight 370 may have gone down on March 8.

Meanwhile, dozens of angry Chinese relatives of missing passengers arrived in Kuala Lumpur Sunday, demanding more information about what happened to the aircraft, accusing Malaysian officials of withholding vital information. About two-thirds of the people on board the jet were Chinese.

The search shifted more than 1,000 kilometers northeast Friday when investigators determined the plane flew faster and burned fuel more quickly than previously estimated. This means the jet did not fly as far as first thought.

The jet disappeared thousands of kilometers west of its intended flight path from Kuala Lumpur to Beijing.

Officials believe the aircraft crashed into the southern Indian Ocean far from land. They have not ruled out any cause, including terrorism or a hijacking.