A DANGEROUS game of tit for tat which pits North Korea against the United States and South Korea appears to be gathering steam on the divided peninsula.

Yesterday, Pyongyang - facing United Nations sanctions for last month's nuclear test - raised the stakes in the growing confrontation by sentencing two US journalists to 12 years' hard labour for a vague "grave crime".

The sentence follows US Secretary of State Hillary Clinton's warning on Sunday that the US was considering putting the North back on its list of states that sponsor terrorism, which would further isolate the impoverished nation.

Journalists Euna Lee and Laura Ling of US media outlet Current TV were arrested in March while working on a story near the China-North Korea border.

Their trial "confirmed the grave crime they committed against the Korean nation and their illegal border crossing",
the official KCNA news agency said.

The harsh sentence will deepen the chill in ties with the US, which has sought for years to get the Stalinist state to give up its nuclear-weapon ambitions.

"We are deeply concerned...and we are engaged through all possible channels to secure their release," State Department spokesman Ian Kelly said. Mrs Clinton had also appealed for the women's release, calling the charges against them baseless.

"(North Korea) is using the sentence as bait to squeeze concessions out of the US amid heightened tension," said Mr Lee Dong Bok of the CSIS think-tank in Seoul, an expert on the North's negotiating tactics.

US President Barack Obama at the weekend called the North's nuclear test last month, which was followed by a series of missile tests, "extraordinarily provocative" and said that this time there would be no appeasement by Washington.

North Korea kept up its rhetoric, which is increasingly unnerving the region, and threatened "extreme" measures if the UN punished it for its nuclear test. It appears to be readying a long-range missile.

The UN Security Council may adopt a new resolution as early as this week, but there is clear division among some members over how tough it should beon the reclusive state.

Many analysts say the belligerence may be aimed at bolstering President Kim Jong Il's position with his own military, to better secure the succession of youngest son Jong Un.

But it's a dangerous game.