Four opposition parties boycotted Diet deliberations Thursday after senior leaders of the ruling bloc rejected claims they forced the Defense Agency to withhold a full report on the information disclosure scandal.

As the impasse continued, a senior Liberal Democratic Party member of the Upper House said there is little possibility for the government package of emergency contingency bills to clear the Diet during the current session.

Although Prime Minister Junichiro Koizumi and the ruling camp are seeking to substantially extend the session beyond its scheduled June 19 close, there is growing pessimism that time is running out for the defense bills, which are still being deliberated in the Lower House.