Thats not true always, here's the data of Trident ICBM
Purpose: strategic nuclear deterrence
Unit Cost: US$30.9 million
Range: 11,300 kilometres (7,000 mi)
Maximum speed: > 6,000 m/s (>21,000 km/h, >13,422 mph).
Guidance system: inertial, with Star-Sighting, GPS experiments done. but not deployed.
CEP: Requirement...90120 m (300400 ft) That demonstrated by flight tests is significantly better.
Warhead (in USA usage only): nuclear MIRV. Up to eight W88 (475 kt) warheads (Mark 5) or eight W76 (100 kt) warheads (Mark 4). The Trident II can carry 12 MIRV warheads but START I reduces this to 8 and SORT reduces this yet further to 4 or 5.
What m saying is that Brahmos II is a hypersonic cruise missile, and it'll fly close the surface thus hard to detect. And given the range of about 300-400km, successful interception chance is very little.