A series of coordinated bombings rocked a packed railway station and crowded Hindu temple Tuesday in the holy city of Varanasi, killing at least 20 people and injuring dozens in an attack that raised fears of communal violence.

Cities across India were put on high alert as Indian Prime Minister Manmohan Singh appealed for calm, said his spokesman, Sanjaya Baru.

"Stern action will be initiated against all those found involved," said Mulayam Singh Yadav, the chief minister of Uttar Pradesh, the state where Tuesday's blasts occurred.

The attacks, which injured at least 62 people, came only days after Hindus and Muslims fought in the streets of Lucknow, leaving four people dead, during a visit to India by President Bush. The next day, angry Hindus looted Muslim shops and burned vehicles in the coastal resort of Goa in a dispute over a mosque demolition.

It was unclear whether Tuesday's bombings in Varanasi, 450 miles east of New Delhi, were the work of anti-government or anti-Hindu militant groups or were connected to Bush's visit.

At least 10 people died in what appeared to be two bombings at Varanasi's train station, and five were killed in another blast at the temple on the banks of the holy Ganges River, said Alok Sinha, a senior state official. Five additional people died overnight of their injuries, Superintendent of Police Paresh Pandey told The Associated Press.

Another senior official, Kamlesh Pathak, said two unexploded bombs — one hidden in a pressure cooker and the other in a backpack — were found at Varanasi's Godowalia Market and defused by police.

The Press Trust of India news agency, meanwhile, reported that security officials found four unexploded bombs at a bathing platform on the banks of the Ganges, a few miles away.

The blast at the Sankat Mochan temple went off near dusk, when the shrine was crowded with Hindus making special Tuesday offerings to the monkey-god Hanuman, said police inspector Madan Mohan Pande.

At least 22 people were wounded in the temple blast, police official Mohammed Hashmi said.

Televised footage showed a man, his face bloodied, lying on a stretcher. An old woman lay on the floor, holding up her arms to helpers, who pulled her away. Debris, body parts and blood covered the temple floor.

Most witness accounts of the blasts at the city's crowded railway station said one bomb went off either in or next to a train car and the other near the ticket counter in the waiting room.

At least 40 people were injured there, 22 of them seriously, Pathak said.

One witness, Sunil Yadav, described a scene of confusion, with people running and screaming.

"It was a high-intensity blast," a man identified only as Pradeep told the CNN-IBN television station. "After the blast people were running like anything."

Varanasi, 450 miles east of Delhi, is Hinduism's holiest city and ordinarily is filled with pilgrims visiting temples and bathing in the holy waters of the Ganges, which runs through the city.

It also is a popular spot with foreign tourists, especially backpackers.

Home Secretary V.K. Duggal said Tuesday's blasts were similar to Oct. 29 bombings in New Delhi that killed 60 people.

Like those blasts, blamed on Islamic militants fighting to wrest predominantly Muslim Kashmir from India, the Varanasi explosions occurred within 10 minutes of each other, Duggal said, according to the Press Trust of India news agency.

While Varanasi is a largely Hindu city, it also has a sizable Muslim population.

Police and paramilitary troops fanned out in Varanasi after Tuesday's explosions, and political leaders, among them top officials for the Hindu nationalist opposition, headed for the city.

The attack on the Hindu holy city came days after Muslims and Hindus battled each other in two other Indian cities, raising fears of a repeat of Hindu-Muslim violence that rocked western India in 2002 after 60 Hindus pilgrims were killed in a train fire initially blamed on Muslims.

That rioting left more than 1,000 people dead over three months. Human rights groups say it was encouraged — and at times outrightly directed — by politicians.

Although officials have not yet said who they believed was behind Tuesday's attack, many in India clearly suspected Muslim extremists.

On Friday, there were clashes in the nearby city of Lucknow after Hindu shop owners refused to respect a general strike called by Muslim leaders to protest Bush's visit to India. Four people were killed.

On Saturday, hundreds of Hindus rampaged through a town in coastal Goa, storming a police station, beating officers, looting Muslim shops and burning vehicles and buildings. The violence came after Muslims demonstrated to protest the demolition of a mosque by suspected Hindu extremists.