April 25 (Reuters) - U.S. defense contractor Northrop Grumman reported a 12% rise in first-quarter profit on Thursday, supported by a global defense spending boost and a robust backlog.

International demand for U.S. weaponry has risen following Russia's invasion of Ukraine and conflicts in the Middle East.

"Robust global defense spending and our strong backlog, along with expanding margins, continue to support our multi-year outlook for free cash flow growth," said CEO Kathy Warden.

Profit in Northrop's Defense Systems segment rose 11% in the first quarter, helped by higher demand for rocket motors and Stand-in Attack Weapon, a tactical air-to-surface missile.

Northrop and L3Harris are the only companies that supply sought-after rocket motors, used in guided multiple-launch rocket systems, that played a crucial role in supporting Ukraine's defense efforts against Russian forces.

Northrop's aeronautic systems business posted a 25% jump in operating income, benefiting from strong demand for E2 Hawkeye aircraft and Lockheed Martin's F-35.

Northrop Grumman, the largest subcontractor for the F-35 jet delivery to Pentagon, has not yet been affected by delays in software updates from Lockheed Martin. However, analysts caution that further delays could potentially hit Northrop.

Last week, Northrop lost on a $17 billion contract to Lockheed to develop the next generation of interceptors to defend the United States against an intercontinental ballistic missile attack.

Sales at Northrop's Space Systems division rose 9% to $3.65 billion in the reported quarter.

Total quarterly sales jumped 9% to $10.1 billion.

Overall profit rose to $944 million, or $6.32 per diluted share, from $842 million, or $5.50 per diluted share, a year earlier. (Reporting by Pratyush Thakur in Bengaluru; Editing by Shinjini Ganguli)