BBC News with Marion Marshall

The United Nations Secretary General Ban Ki-moon has joined South Korea and several major powers in a strong condemnation of North Korea's shelling of a South Korean island, which killed several soldiers and injured dozens of people. South Korea's President Lee Myung-bak ordered the army to

retaliate

with missile strikes in the event of further North Korean attacks. The US State Department described the shelling as a stunning provocation. From the UN, here is Barbara Plett.

Ban Ki-moon said the artillery attack was one of the gravest incidents since the Korean War ended in 1953. He condemned it and called for immediate

restraint

. In a telephone call, he

convey

ed his concerns to the current president of the Security Council, the British ambassador Mark Lyall Grant. Mr Lyall Grant told reporters he was

in touch with

council members about what to do next. No country has formally requested an emergency session, and the UN will wait to hear what South Korea might want from such a meeting. But North Korea's deputy ambassador said this was something that should be discussed by the two Koreas and not by the Security Council.

Defence analysts in Washington say the insurgency in Afghanistan is growing in strength and that levels of violence have reached new highs. In a report to Congress, the analysts say combat incidents have increased

threefold

since 2007. From Washington, Kevin Connolly reports.