A female suicide bomber blew herself up near an entrance to the US-protected Green Zone and a bomb tore through a minibus carrying Iraqi government employees in separate attacks yesterday that killed at least 20 people, Iraqi officials said.

Three more people were killed in bomb attacks on police patrols in Baghdad and Baqouba, northeast of the capital, police said.

The violence came as Iraqi lawmakers prepared for a vote tomorrow on a security pact with the United States that would enable American forces to stay in Iraq for up to three more years under strict Iraqi oversight.