By Bill Hayton
BBC News, Hanoi
The first minister to appear before a session of Vietnam's National Assembly, which is investigating corruption allegations, has been questioned.
Transport minister Dao is the focus of much speculation
The minister, head of public security Le Hong Anh, was asked about wrong-doing in three scandals linked to the ministry of transport.
The Assembly is eagerly awaiting the appearance of the transport minister.
The Assembly has been little more than a rubber stamp for decisions taken by the Communist Party leadership.
In this session, however, it has begun raising a more independent voice.
Members of the Assembly want to know who is to blame for a series of corruption scandals involving bribery, nepotism and illegal gambling in agencies linked, in particular, to the transport ministry.
The first to appear before the Assembly, the Public Security Minister Le Hong Anh, faced a barrage of angry questions.
Mr Anh was asked who was to blame for the scandals in which many millions of dollars are alleged to have been stolen from a road building unit known as PMU-18, Vietnam Airlines and the country's main port of Hai Phong.
The hearings are being broadcast live on radio and television and there is a sense of expectation ahead of the testimony of the transport minister.
He has already offered to resign but remains in post for the time being.