India, May 29 -- Siddaramaiah resigned as Karnataka chief minister on Thursday, ending months of uncertainty over the Congress leadership transition in the state and potentially clearing the way for his deputy and challenger DK Shivakumar to assume office.

Siddaramaiah held a breakfast meeting with his cabinet colleagues, including Shivakumar, then drove to Lok Bhavan at 2.45pm. The resignation letter was submitted to Prabhu Shankar, special secretary to Governor Thaawarchand Gehlot, who is currently outside the state and was expected to return later on Friday. Formal acceptance of the resignation is likely only after his return.

At a joint press conference with Shivakumar and state home minister G Parameshwara, Siddaramaiah said he act...