An earthquake struck Serbia early Wednesday, killing two people, injuring dozens and causing substantial damage in the central city of Kraljevo, where electricity and other services were cut.

The 5.6-magnitude quake hit at 1:56 am (0056 GMT) with its epicentre 10 kilometres (six miles) north of Kraljevo, which lies 150 kilometres (95 miles) south of the capital Belgrade, the Serbian seismological institute said.

"A couple in their 50s was killed at Grdica, a suburb of Kraljevo, in the earthquake during the night," the interior ministry said in a statement.

Two women were admitted with serious injuries, which were not life threatening, Health Minister Tomica Milosavljevic told Beta news agency, adding that "dozens of people received medical treatment."

Rescue teams have been deployed but had not found anyone trapped under the rubble, police said.

The tremor, one of the strongest in the country in the last 30 years, badly damaged the city of Kraljevo and some surrounding villages.

Local authorities declared an emergency situation, enabling them to get help nationally as local services could not cope.

The finance ministry said it had opened a special account to raise funds for victims in Kraljevo.

In the village of Vitanovac, the epicentre of the quake, some 70 percent of houses were severely damaged, many with their roofs collapsed. Some inhabitants were seen replacing fallen tiles.

Zivan Milivojevic, 70, was trying to estimate the damage to his house.

"My entire home is destroyed, 40 years of work gone. The house is no longer habitable," Milivojevic told AFP, showing a wall clock that fell and stopped at 1:59.

Following the quake Kraljevo was plunged into darkness as power was cut while phone lines and water supplies were also severed, local media reported.

According to Kraljevo mayor Ljubisa Simovic, 10 hours after the tremor some 25 percent of the city was still out of electricity and some parts had no heating.

Inhabitants have been warned not to use water until the quality was checked by special teams coming from Belgrade and the neighbouring towns of Cacak and Kragujevac.

Some school buildings suffered substantial damage, as well as the city hall.

The hospital was also damaged, notably its operating theatres, and Milosavljevic said some wards, including the maternity ward, had been closed because of flooding caused by broken water pipes.

Defence Minister Dragan Sutanovac, who visited several military facilities in the area, said army barracks in Kraljevo were also severely damaged, but nobody was hurt, Beta reported.

Many shop windows were broken, while some cars were destroyed by concrete blocks falling.

The quake was felt across the country, including Belgrade.

The US Geological Survey measured it at 5.3 magnitude at a relatively shallow depth of 10 kilometres.

It was followed by four other less powerful aftershocks, the Serbian institute said.