The United States and Cuba ended two days of historic talks in Havana with some progress toward restoring diplomatic ties after half a century of estrangement.
But there remain sharp differences over the role of human rights in their new relationship.
"As a central element of our policy, we pressed the Cuban government for improved human rights conditions, including freedom of expression," said Roberta Jacobson, the senior US diplomat for Latin America and most senior American official to visit the island country in more than three decades.
In Spanish, however, her statement said the US "pressured" Cuba on the issue.
"Cuba has never responded to pressure," Josefina Vidal, Cuba's senior diplomat for US affairs, responded.
The comments reflected long-standing positions of their governments and it was not clear whether the issue, which has previously blocked closer US-Cuban relations, would pose a threat to the new diplomatic process.
Yet it laid bare the pressures each side faces at home - the US, from Republican leaders in Congress and powerful Cuban-American groups and Cuba, from hardliners deeply concerned that rapprochement could undermine the communist system founded by Fidel Castro.
In the first face-to-face talks since last month's declaration of detente, the two countries laid out a detailed agenda for re-establishing full diplomatic relations. Further talks were planned.
Ms Jacobson hailed the discussions as "positive and productive," focusing on the mechanics of converting interest sections into full-fledged embassies headed by ambassadors.
But she also spoke of "profound differences" separating the two governments and said embassies by themselves would not mean normalised ties.
"We have to overcome more than 50 years of a relationship that was not based on confidence or trust," she said.
Along with human rights, Cuba outlined other obstacles in the relationship. Ms Vidal demanded that Cuba be taken off the US list of state sponsors of terrorism.
However, she praised President Barack Obama for easing the US trade embargo and urging the US Congress to lift it entirely.
"It was a first meeting. This is a process," she said. In the next weeks, she added, the US and Cuba will schedule a second round of talks, which may or may not be the time to finalise an agreement.
Issues on yesterday's agenda included ending caps on staff, limits on diplomats' movements and, in the case of the US building, removing guard posts and other Cuban structures along the perimeter.
The US and Cuba also talked about human trafficking, environmental protection, American rules to allow greater telecommunications exports to Cuba and how to co-ordinate responses to oil spills or Ebola outbreaks.
The need for at least one future round of talks could set back US hopes of reopening the embassies before April's Summit of the Americas, which Mr Obama and Mr Castro are expected to attend.