The Pentagon declined Monday to comment on North Korea's recent failed test of a submarine-launched ballistic missile, citing intelligence matters.

Yonhap News Agency reported that the North fired a KN-11 missile from a submarine in the East Sea on Saturday, but the test ended in failure as the missile failed to soar from the waters.

"As far as whether North Korea attempted an SLBM launch, we will not discuss intelligence matters," said Cmdr. Bill Urban, a U.S. Defense Department spokesman.

In May, North Korea claimed it successfully carried out an SLBM test underwater, renewing tensions on the Korean Peninsula amid concern that the North's SLBM capability, if fully developed, would pose a serious threat because its mobile nature would make it very difficult to detect preparations for a launch.

But experts said it was believed to be not a full-scale test, but an "ejection" test conducted in an early stage of developing SLBM capabilities. U.S. officials said the North also exaggerated progress and is many years away from developing an SLBM. (Yonhap)