A bomb blast at the airport just outside the capital of Laos has injured at least four people.

The bomb was in a bag attached to a bicycle left outside the domestic air terminal at Vientiane's Wattai airport. A crude homemade device, it reportedly contained shards of metal.

Four women, who were apparently employees at the airport, were injured in the explosion. One of them suffered serious injuries.

No one has claimed responsibility for the blast, which is the latest of about 10 explosions in the city since spring.

Some believe the attacks stem from a split in the Laotian government factions leaning toward China or Vietnam.

The latest blast has created concern about security as Chinese President Jiang Zemin is scheduled to visit Laos this weekend. And Vientiane is set to host a meeting of foreign ministers from the Association of South East Asian Nations and the European Union in December.

Officials say all precautions have been taken and the meeting will go ahead.