Officials in the Kenyan port city of Mombasa have impounded more than 600 pieces of ivory, weighing two tonnes, they said Tuesday, the latest in a series of seizures by Kenyan authorities.

"They were labelled as decorating stones and were headed to Indonesia from Tanzania," a police source based at the port told AFP on condition of anonymity.

The head of operations at the port, Gitau Gitau, confirmed the seizure, but said no arrests had been made. Gitau said the documents used to ship the cargo would be used to track its owners, and added that the seized ivory is valued at more than $1 million (750,000 euros).

Two weeks ago, officials in Hong Kong seized more than a tonne of ivory worth about $1.4 million in a shipment from Kenya.

The international trade in elephant ivory, with rare exceptions, has been outlawed since 1989 after elephant populations in Africa dropped from millions in the mid-20th century to some 600,000 by the end of the 1980s.

Ivory trade is banned under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

East African nations have recently recorded an increase in poaching incidents. A week ago, a family of 11 elephants was killed in a Kenyan park in what officials called the country's worst incident of its kind in the past three decades.

The killing led to an aid appeal by Kenya's Prime Minister Raila Odinga to help the country deal with the escalating poaching menace. Despite the fact that tourism plays a major role in east African economies, poachers have recently expanded their operations to areas previously thought to be safe from poaching.

According to the Kenya Wildlife Service, Kenya lost at least 360 elephants last year, up from 289 killed in 2011.

In October last year, Tanzanian police seized over 200 elephant tusk pieces valued at around $1 million dollars from 91 different animals.

Four people were also arrested in the raid and a total of 214 tusk pieces were recovered from the house of a Kenyan living in Tanzania's economic capital Dar es Salaam, officials said.

At the time of the arrests, police said they believed the ivory came from elephants in Tanzania, and that smugglers had hoped to take the tusks by road into Kenya.

Some experts have attributed the increase in poaching to an upcoming meeting of signatories to the CITES treaty in Thailand in March, which may be prompting ivory dealers to boost their stocks in speculation that the conference might result in a lift of the ban on the ivory trade.

The illegal ivory trade is mostly fuelled by demand in Asia and the Middle East, where elephant tusks and rhinoceros horns are used to make ornaments and in traditional medicines.

Africa is home to an estimated 472,000 elephants, whose survival is threatened by poaching and the illegal trade in game trophies, as well as a rising human population that is causing habitat loss.