SINGAPORE (Reuters) - U.S. Defense Secretary Robert Gates on Thursday sought to reassure South Koreans of Washington's support in the face of what he called provocations from "an even more unpredictable" North Korea.

Speaking in Singapore, Gates also said Washington and Seoul were considering conducting additional anti-submarine exercises as tensions rise after the sinking of a South Korean warship, which has been blamed on the North.

"An important element ... will be to reassure the South Koreans of our support as they face these provocations. The North, it seems even more unpredictable than usual," Gates said.

(Reporting by Adam Entous; Editing by Paul Tait)