CANBERRA, March 20 -- The radar hits seen Thursday by a U.S. P-8 aircraft searching for missing Malaysia Airlines flight MH370 are not linked to the suspicious objects identified by Australian authorities, the U.S. 7th Fleet said.

The radar hits were "typical radar returns that air crew sees on a routine basis," the commander of the 7th Fleet, William Marks, told Xinhua in an emailed statement.

Earlier in the day, the P-8 aircraft picked up radar signals indicating a large object in the southern Indian Ocean, U.S. broadcaster ABC quoted its correspondent David Wright, who is onboard the P-8 plane, as reporting. The report said that the radar is getting "hits of significant size" and that the crew are trying to get visuals.

Australian authorities said Thursday that two objects have been spotted in the southern Indian Ocean on satellite imagery that might be related to the missing Malaysian jetliner.

However, Marks said the two were not linked. "The radar returns on the P-8 were not associated with the announcements by the Australian prime minister earlier today -- it seems it was just coincidental timing," he said, adding, "We have no indication of debris from the MH370 wreckage."

The U.S. 7th Fleet said it's "working closely in support of the Australian-led effort in this sector."

John Young, an official from the Australian Maritime Safety Authority, said earlier Thursday at a briefing that one of the objects is as large as 24 meters in size while the other is smaller.

Australia has dispatched aircraft and ships to locate the objects, which Young said were "probably the best lead we have right now."