(For more on Afghanistan, click on [nAFPAK])

* Obama promises to announce his decision "shortly"

* Television address expected next Tuesday evening

* Military chiefs favor 30,000-plus troop increase (Updates with analyst)

By Jeff Mason and Adam Entous

WASHINGTON, Nov 24 (Reuters) - U.S. President Barack Obama vowed on Tuesday to "finish the job" of an unpopular and costly eight-year war in Afghanistan, and officials said he could announce an increase of around 30,000 troops next week.

Obama said he would soon end weeks of intense speculation about his plans for the way forward in Afghanistan, after a three-month strategic review that has drawn fire from Republican critics who accuse him of dithering.

"After eight years, some of those years in which we did not have, I think, either the resources or the strategy to get the job done, it is my intention to finish the job," Obama said at a news conference with Indian Prime Minister Manmohan Singh.

"I will be making an announcement to the American people about how we intend to move forward. I will be doing so shortly," he said.