US has signed a $3 billion deal with Lockheed Martin and Northrop Grumman to boost production of Patriot and THAAD air defence system missile parts, the Pentagon said. This comes after a $58.6 billion Lockheed Martin deal last week to produce Patriot interceptor missiles. The deal will triple PAC-3 missiles for Patriot and quadruple those for THAAD systems, it added.