US Secretary of State Hillary Clinton says the prayers of Americans are with trapped workers inside a New Zealand mine, and their families.
There has been no communication with the miners and contractors at the Pike River Coal mine near Greymouth since a methane gas explosion cut power and blew out ventilation fans about 3.45pm on Friday.
Mrs Clinton issued the statement of support through the US embassy in Wellington on Sunday, which she says is monitoring the situation at the mine closely and is standing ready to provide technical assistance.
After her visit to earthquake damaged Christchurch earlier in November Mrs Clinton says she witnessed first-hand the courage and resilience of New Zealanders.
She says she hopes the 29 men still inside the mine are safe and will be rescued, and that her thoughts go out to those affected by the disaster and all the people of New Zealand.