WASHINGTON (AFP) - The US military will drastically increase drone flights over the next four years, in a bid to boost intelligence and strike capabilities across a growing number of conflict zones, the Wall Street Journal reported.

The Pentagon is planning to expand the number of daily flights from 61 at present to as many as 90 by 2019, a senior defence official told the Journal.

The move represents the first significant increase in the controversial US drone program since 2011, reflecting the rise in global hotspots.

As well as providing extra surveillance in regions such as Ukraine, Iraq, Syria, the South China Sea and North Africa, the new plan would expand the Pentagon's capacity for lethal drone air strikes.

That program, which has expanded massively under President Barack Obama, is the subject of frequent criticism from observers who say the highly secretive drone raids have killed many innocent civilians.

Non-partisan groups say US drone strikes have killed at least 3,000 people, the Journal reported on Sunday.

Under the new plans, the US Air Force, which currently carries out the bulk of drone missions, would get help from the Army, Special Operations Command and government contractors.