UPDATE 1-U.S. transport chief reviewing fatal Boeing plane crashes 'very carefully'

U.S. Transportation Secretary Elaine Chao said Monday that U.S. regulators are "very carefully" reviewing the fatal crashes of two Boeing Co 737 MAX 8 planes.

Chao said she met with the Federal Aviation Administration's acting chief to review both Sunday's Ethiopian Airlines crash and October's Lion Air crash and to ask "what are possible paths going forward ... I want people to be assured that we take these incidents, these accidents very seriously." Boeing's share price dropped 10 percent in early trading on Monday at the prospect that two such crashes in such a short time could reveal flaws in its new plane.

The 737 line, which has flown for more than 50 years, is the world's best-selling modern passenger aircraft and viewed as one of the industry's most reliable. (Reporting by David Shepardson; Editing by Lisa Shumaker and James Dalgleish)