LONDON (AP) — A law that will enable Britain to send some asylum-seekers on a one-way trip to Rwanda suffered a setback on Wednesday after Parliament’s upper chamber pressed its attempt to amend the contentious legislation.

The House of Lords inserted amendments into the Safety of Rwanda Bill, sending it back to the lower House of Commons in a process known as parliamentary ping-pong.

The government had hoped members of the Lords would stop blocking the bill on Wednesday, relenting to the parliamentary rule that the unelected Lords ultimately can’t overrule the elected Commons. The Lords’ resistance underlines the strength of opposition in the upper house, where the governing Conservative Party does not have a majority.

The bill is still overwhelmingly likely to become law, but the latest move delays its passage, likely until next week.