U.S. President Donald Trump shakes hands with Ukraine's President Petro Poroshenko in the Oval Office at the White House in Washington, U.S. June 20, 2017. REUTERS/Jonathan Ernst

WASHINGTON (Reuters) - All parties to the Minsk agreement to end fighting in Ukraine want to cooperate with the United States, and Washington is considering appointing an envoy to the negotiations, a senior U.S. State Department official said on Wednesday.

Secretary of State Rex Tillerson, who is due to visit Ukraine next week, said last month the United States should not be “handcuffed” to the 2015 Minsk agreement in case the parties decide to reach its goals through a different deal.

The senior State Department official told reporters all parties to the agreement “have asked for a U.S. interlocutor that they can work with - some sort of Minsk coordinator or envoy ... and we are actively considering that.”

The Minsk peace agreement, brokered by France and Germany and signed by Russia and Ukraine, calls for a ceasefire, the withdrawal of heavy weapons from the front line and constitutional reform to give eastern Ukraine more autonomy.

Tillerson will meet with Ukrainian President Petro Poroshenko during his visit to Kiev, on July 9, said the official, who spoke to reporters on condition he was not named.

Poroshenko said after meeting with President Donald Trump and other U.S. officials in Washington last month that the two countries would soon sign a number of agreements boosting defense cooperation. Ukraine’s foreign minister said the deal would involve defensive weapons only.

Asked about a possible defensive weapons deal, the State Department official said: “We’ve neither ruled out providing such weapons to Ukraine, nor have we taken a decision to do so.”