(VOVworld) - Senior defense officials from South Korea and the US opened a new round of talks Wednesday to determine how long to delay the planned transfer of wartime operational control (OPCON) of South Korean troops from Washington to Seoul.

Ryu Je-seung (R), chief of the Office of Planning and Coordination of South Korea's Ministry of National Defense, shakes hands with David Helvey, deputy assistant secretary of defense for East Asia, on June 16, 2014, ahead of their talks on the timing of and conditions for the transfer of the operational control of South Korean armed forces from Washington to Seoul

This week's talks, set to last through Thursday, are considered crucial because it could be the last round before the allies hold their annual defense ministerial meeting in Washington in October, when they are expected to announce an agreement. It is the second "executive session" the two countries have held since April, when South Korean President Park Geun-hye and US President Barack Obama decided that the timeline for the transition of OPCON, currently slated for 2015, should be reconsidered. The two leaders agreed to have their governments work together to determine the "appropriate timing and conditions” for the transition of OPCON.