South Korea's government has assured parliament it will carefully consider all risks as it considers plans to pipe natural gas across North Korea from Russia.

Officials provided the assurance in a report to parliament Monday, just days after South Korean President Lee Myung-bak said work on the proposed pipeline could proceed more quickly than expected.

Russian natural gas giant Gazprom said Thursday that officials from North and South Korea have agreed to create a joint working group on implementing the plan, which would be highly profitable for all three countries and could boost efforts to mend relations between the two Koreas.

But critics in South Korea warn the North could threaten to shut down the pipeline for political reasons at any time.

South Korea has contracted to purchase as much as 10 billion cubic meters of .natural gas a year from Russia beginning later in this decade. The gas could be delivered by pipeline for about one-third of the cost of sending it by ship, while North Korea would be able to charge transit fees estimated at up to $500 million a year.

Russia asked for North Korea's cooperation on the plan in mid-August, and said North Korean leader Kim Jong Il promised his support at a summit with Russian President Dmitry Medvedev later that month .

Mr. Lee said in a television interview this month that the project could proceed faster than expected because it would benefit all sides. Mr. Lee was involved in earlier talks on a pipeline deal when he was president of Hyundai Engineering and Construction in 1989.

The growing interest in the pipeline proposal accompanies a series of recent efforts to repair inter-Korean relations, which have been at a low ebb since two military attacks on South Korean targets last year.

Envoys for the two Koreas will meet in Beijing on Wednesday to try to create an environment for the resumption of six-nation talks on North Korea's nuclear programs, while South Korea has begun allowing private groups to deliver some food aid to the North.

South Korea also replaced its unification minister, who is primarily responsible for relations with the North, with an official who is promising to work for better relations.