Suspected communist rebels used a homemade bomb to attack a jeep carrying election officials, injuring two people, as voting began Thursday in the second round of India's monthlong national elections, officials said. Government forces were on high alert as thousands of people crowded polling stations early in the day to avoid blazing summertime temperatures touching 44 Celsius in parts of the eastern states of Orissa, Jharkhand and Bihar. Reflecting the myriad differences of India's electorate, few expected a clear winner after a lackluster campaign that has been devoid of resonant, central issues. On Wednesday, communist rebels briefly hijacked a train carrying 300 passengers, later releasing them unharmed, and carried out other attacks aimed at disrupting the polls. A truck driver was killed by suspected rebels on a highway in Bihar, considered one of the most lawless states, said Neelmani, a local police official who uses only one name.