The Sri Lankan military launched an offensive, called "Operation Liberation" or Vadamarachchi Operation, during May–June 1987 to regain control of the territory in the Jaffna peninsula from the LTTE. This marked the Sri Lankan military's first conventional warfare on Sri Lankan soil since independence. The offensive was successful, and LTTE leader Prabhakaran and Sea Tiger leader Thillaiyampalam Sivanesan "alias" Soosai narrowly escaped from advancing troops at Valvettithurai. Key military personnel involved in the operation were Lt Col. Vipul Boteju, Lt. Col. Sarath Jayawardane, Col. Vijaya Wimalaratne and Brig. Gen. Denzil Kobbekaduwa.