Gordon Brown has urged Pakistan president Pervez Musharraf to go ahead with elections next month.
The planned January 8th polls have been cast into doubt by yesterday's assassination of former leader Benazir Bhutto after a political rally in Rawalpindi.
But the British prime minister has today spoken to his Pakistani counterpart on the phone and expressed his desire for them to go ahead as planned.
Mr Brown also passed on his condolences to the people of Pakistan during the call and condemned the killing of the two-time prime minister.
"The international community is united in its outrage and determination that those who stoop to such tactics shall not prevail," Mr Brown said in a Downing Street statement.
"I therefore encouraged President Musharraf to stick to the course he has outlined to build democracy and stability in Pakistan."
Mr Brown called the killing of the 55-year-old, whose body was today buried, a "cowardly terrorist act designed to destabilise democratic elections".
He also said that the "deadly attack" was a "potent reminder of the threat we face from terror".
The Pakistan government has blamed al-Qaida for yesterday's killing and Mr Brown has today offered British support in the fight against the terror network.
"Pakistan is a major ally in the global effort to combat this menace," the PM said.
"I told President Musharraf that the UK is prepared to sustain and build the already significant counter-terrorism support we offer his country, not least in the effort to destroy al-Qaida."
Ms Bhutto was laid to rest at a family mausoleum near her home village in Sindh province this afternoon as investigations into her murder continue.