Honduras' electoral authority pleaded for calm on Tuesday as it scrambled to overcome a system failure that left about 20% of votes in the presidential election uncounted, as U.S. President Donald Trump hurled allegations of possible fraud and swore "there will be hell to pay" if results are altered.

Nasry Asfura, the Conservative National Party candidate backed by U.S. President Donald Trump, leads Honduras' presidential election with just over 40% of votes counted, preliminary results showed on ...