LISBON, Portugal (AP) — A prominent Venezuelan opposition activist said Wednesday that his movement’s recent offer to negotiate with President Nicolás Maduro’s administration was prompted by the country’s urgent humanitarian crisis and prolonged political stalemate.

Leopoldo Lopez told the Associated Press that his opposition group has not yet received a response to its proposal from the Maduro government. The two sides have for years been locked in a standoff.

Lopez is close to Juan Guaidó, the opposition leader recognized by the U.S. and dozens of other countries as Venezuela’s legitimate leader. Guaidó on Tuesday offered to work with Maduro’s administration toward a “National Salvation Agreement.”

Guaidó said any agreement must be reached through negotiations involving the opposition, pro-government forces and the international community.

Lopez, who was in Portugal after trips to Italy, the Vatican and the Netherlands to seek backing for Guaidó’s proposal, said “the political crisis ... is at the heart of our problem.”

The opposition want talks to be “very focused” on addressing the immediate humanitarian crisis, including the rollout of COVID-19 vaccines, on agreeing a path to presidential and parliamentary elections with international observers, as well as a timeline for those steps and the gradual lifting of international sanctions on Venezuela.

Lopez said previous efforts at negotiation had failed because there were too many issues on the table.

Guaidó’s supporters are also presenting the plan to authorities in Latin America and the United States.