Eelam War IV is the name given to the fourth phase of armed conflict between the Sri Lankan military and the separatist Liberation Tigers of Tamil Eelam (LTTE). Renewed hostilities began on the 26 July 2006, when Sri Lanka Air Force fighter jets bombed several LTTE camps around Mavil Aru anicut. The government's casus belli was that the LTTE had cut off the water supply to surrounding paddy fields in the area. Shutting down the sluice gates of the Mavil Aru on July 21 depriving the water to over 15,000 people - Sinhalese and Muslim settlers under Sri Lankan state-sponsored colonisation schemes in Trincomalee district. They were denied of water for drinking and also cultivating over 30,000 acres of paddy and other crops. The fighting resumed after a four-year ceasefire between the Government of Sri Lanka (GoSL) and LTTE. Continued fighting led to several territorial gains for the Sri Lankan Army, including the capture of Sampur, Vakarai and other parts of the east. The war took on an added dimension when the LTTE Air Tigers bombed Katunayake airbase on March 26, 2007, the first rebel air attack without external assistance in history.

The Liberation Tigers of Tamil Eelam was a Tamil militant organization that was based in the northern and eastern Sri Lanka. The LTTE fought to create an independent Tamil state called Tamil Eelam in the northeast of the island in response to violent persecution and discriminatory policies against Sri Lankan Tamils by the Sinhalese-dominated Sri Lankan Government.