Uribe keen to cement pact with US

"I commended president Uribe on the progress that has been made on human rights in Colombia and dealing with the killings of labour leaders," Obama said.

But "President Uribe acknowledges that there remains more work to be done", he said.

Colombia has tried to get the US congress to ratify a free trade deal that George Bush, Obama’s predecessor, signed in 2006.

The agreement has been held up amid concerns among Democrats, who control congress and now the White House, about Colombia’s human rights record.