Two blasts ripped through the oil hub city of Atyrau in western Kazakhstan Monday, killing a suspected suicide bomber but causing little damage.

No one else was hurt in the attacks, which began just before 9 a.m. local time (4:00 a.m. British time) with a blast near an administrative building in the Caspian port city, about 2,500 km (1,553 miles) west of the Kazakh capital Astana.

An hour later there was a large blast near the offices of the city's prosecutors, police and national safety committee, regional prosecutors said.

An unidentified man used an explosive device, making him die on the spot and breaking the windows of a nearby apartment building, they said in a statement.

It was not clear whether they considered the same man responsible for both blasts.

Kazakh news site Tengrinews.kz, citing a source in the security forces, said the bomber's body parts were scattered around the site of the blast and that he was a suicide bomber.

The blasts occurred dozens of kilometres (miles) from Kazakhstan's oilfields, which stretch along the Caspian Sea coast to the south and west of Atyrau, a base of operations for Kazakh and international oil companies.

Oil production facilities appeared to be unaffected.

The blasts are the latest to befall oil-rich Kazakhstan, a normally peaceful majority Muslim former Soviet country in Central Asia. In May two blasts killed several people.

A week ago, a previously unknown Islamist group threatened Kazakhstan in a video with violence unless it abolished a new law banning prayer rooms in state buildings.

President Nursultan Nazarbayev, who has run Kazakhstan for 20 years, this month signed a new religion law which bans prayer rooms in state buildings and requires all missionaries to register with authorities every year.

Analysts say the violence could signal an intensifying power struggle among security forces or a spillover from neighbouring states. Tajikistan, which borders Afghanistan to its south, is struggling with violence linked to Islamist jihadist ideology.

Atyrau is an administrative and residential centre for international oil groups such as Chevron-led Tengizchevroil, which operates Kazakhstan's largest producing oilfield, Tengiz, to the south of the city.

Today the office in Atyrau and in Tengiz are working normally. The company has raised security, Linsi Crain, a spokeswoman for Tengizchevroil in Atyrau, told Reuters by telephone.

U.S. oil majors ExxonMobil and ConocoPhillips have offices in the city, as does Italy's ENI, part of the consortium developing the giant Kashagan field some 80 km from the city.

A spokesman for a Kazakh energy company, MangistauMunaiGas, also told Reuters its operations were unaffected. We are continuing to pump oil, he said.

Atyrau is home to one of Kazakhstan's four refineries, but the plant is located in a different part of town, far from the blast sites.

All is calm here, refinery spokeswoman Yelena Yesenova told Reuters by telephone.

(Reporting by Maria Gordeyeva, Olga Orininskaya and Alla Afanasyeva; writing by Amie Ferris-Rotman and Melissa Akin; editing by Philippa Fletcher)