May 4 (Reuters) - Amgen said on Monday it was investing an additional $300 million in Puerto Rico to expand its U.S. manufacturing network.

Global drugmakers have been boosting manufacturing in the country in response to President Donald Trump's tariffs that could reach 100% on imported branded medicines.

-- Amgen said the investment will expand its Juncos, Puerto Rico-based biologics manufacturing facility, which distributes medicines to more than 60 countries.

-- This adds to the drugmaker's previously announced investments of $650 million in Puerto Rico last year, expected to create 750 jobs.

-- Trump signed an executive order in April imposing 100% tariffs on branded pharmaceuticals imported into the U.S. unless manufacturers agreed to government drug-pricing deals or committed to making their products domestically.

-- Amgen over the past year has announced planned investments, including $900 million in Ohio and $600 million in a science and innovation center in California. It has also invested more than $1.5 billion in North Carolina.