Dhaka, April 5 -- US President Donald Trump's widest-ranging tariffs to date have come into effect - a move that may trigger retaliation and escalate trade tensions, upsetting the global economy.

The initial 10 per cent "baseline" tariff took effect at United States seaports, airports and customs warehouses at 12:01am ET (04:01am GMT) on Saturday, ushering in Trump's full rejection of the post-World War II system of mutually agreed tariff rates.

Among countries first hit with the 10 per cent tariff are Australia, Britain, Colombia, Argentina, Egypt and Saudi Arabia.

Thetrade gaps, said the White House, were driven by an "absence of reciprocity" in relationships and other policies like "exorbitant value-added taxes."

A US Customs and B...