Top US and British diplomats made a surprise trip to Iraq on Sunday to prod the country’s struggling leaders to end nearly four months of wrangling and form a new government. ‘‘We’re going to urge that the negotiations be wrapped up,’’ US Secretary of State Condoleezza Rice said as she and British Foreign Secretary Jack Straw flew to the Iraqi capital for meetings with the current interim government and ethnic and religious power brokers.

Straw said the choice of leaders is up to Iraqis alone, but neither he nor Rice disguised the nature of their mission. ‘‘There is significant international concern about the time the formation of this government is taking, and therefore we believe and we will be urging the Iraqi leaders we see to press ahead more quickly,’’ Straw said.

‘‘We’ve wanted to be out there at times that we thought we could help move the process forward,’’ Rice said. ‘‘And of course it’s important to have fresh messages from time to time from Washington and from London about the concern that a government be formed.’’

Britain is Washington’s closest ally in the Iraq war and stations the second largest number of troop in the country after the US.

Rice and Straw were meeting with President Jalal Talabani. Meetings were also planned with Vice-President Adil Abdul Mahdi and Prime Minister Ibrahim al Jaafari. The visit comes amid growing pressure on al-Jaafari to step aside as the Shi’ite nominee for a second term to break the stalemate in talks on forming a new government.