Malaysia's influential former Prime Minister Mahathir Mohamad quit the ruling party May 19 after a long feud with his successor, deepening the cracks that appeared after the party's recent massive electoral losses.

In a speech to about 1,000 people, Mahathir said his decision to leave the United Malays National Organization party was prompted by his lack of confidence in Prime Minister Abdullah Ahmad Badawi.

The surprise decision is expected to intensify the crisis for Abdullah who is facing calls from many of his own party members to resign to take responsibility for the party's losses in the March 8 general election.