MUMBAI (AFP) - Three Indian states went to the polls Tuesday in the first test for the ruling Congress party alliance since it won a thumping general election victory in May on promises of economic reform.

Campaigning for state elections in Maharashtra, Haryana and Arunachal Pradesh focused on relief for drought-hit areas after a poor monsoon, electricity shortages, unemployment and rising food prices.

The Congress power trio of Prime Minister Manmohan Singh, party president Sonia Gandhi and her son Rahul Gandhi toured the states ahead of voting, with much attention focused on the vast city of Mumbai, the capital of Maharashtra.

Key concerns in Maharashtra range from improving security after the Mumbai attacks last year in which 166 people died, the recent slowdown in economic growth, and rural poverty that has triggered a spate of farmer suicides.

"There is no single decisive vote factor," Kumar Ketkar, analyst and editor of Marathi newspaper Loksatta, told AFP, describing the campaign as "bitter and chaotic".

Voting on Tuesday was largely peaceful, though police said Maoist rebels opened fire at one polling booth near where 17 officers were gunned down last week.

The Congress alliance has ruled for 10 years in Maharashtra, and Ashok Chavan was battling to retain the chief minister role that he took over soon after the attacks on Mumbai.

The main opposition is an uneasy alliance between two Hindu nationalist parties -- the regional right-wingers Shiv Sena, and the Bharatiya Janata Party (BJP), who have struggled since their heavy defeat in national elections.

Chavan appealed for Maharashtra's voters to judge him on his record.

"In the last six to seven months the police have done a good job. The trial of (militant attacks suspect) Kasab is progressing fast," he said while campaigning.

"A lot of money has been sanctioned to procure weapons and equipment for the police."

Among those who voted in Mumbai were Bollywood heartthrobs Salman Khan and Priyanka Chopra, cricket hero Sachin Tendulkar and industrialist Anil Ambani.

"We want someone who tackles issues such as power and water supply, which are being ignored," said local resident Izaz Ahmed as he cast his ballot with his wife Sara.

Prime Minister Manmohan Singh, campaigning in the city at the weekend, said that price rises caused by the poor monsoon would soon be reversed and he reassured voters that "the worst is indeed over."

BJP leader L.K. Advani, however, targeted Singh at a series of election rallies.

"Where there is corruption, there is price rises," he said. "Corruption is the cause of price rises and the prime minister had failed to check the corruption."

Shiv Sena, founded by Bal Thackeray in 1966, has a reputation for flaming inter-faith tensions and targeting India's Muslim minority. Thackeray, 83, remains at its head but the movement has become increasingly fractured.

His nephew Raj Thackeray heads the breakaway MNS, which may split the Hindu nationalist vote. Raj was briefly arrested last year on charges of disrupting government work and rioting.

Haryana state, near to Delhi, is a well-populated agricultural and industrial region, while remote Arunachal state in the mountainous northeast borders China.

About 90 million people were eligible to vote in the elections, with the result due to be announced on October 22.