British Prime Minister Tony Blair has spoken to South African leader Thabo Mbeki about the deepening crisis in Zimbabwe.
The talks come amid concerns that Britain is deporting Zimbabwean asylum seekers back to their country to face death or torture at the hands of President Robert Mugabe's secret police.
Mr Blair insists that anyone with a legitimate claim for asylum would stay - but those without would be sent back.
Downing Street says the situation will be monitored closely but each case will be tested on its merits.
Reports claim members of the opposition Movement for Democratic Change are being arrested or attacked on their return to Zimbabwe.
The Refugee Council says people's lives were at risk because of Government policy, while shadow home secretary Oliver Letwin has called for an all-party meeting on the claims.
During their telephone call, the Prime Minister and President Mbeki agreed the situation in Zimbabwe was very serious.
"It is clearly deteriorating in a way that is giving everyone cause for concern," Mr Blair's spokesman said.