A British warship arrived in Guyana on Friday afternoon amid rising tensions from a border dispute between the former British colony and Venezuela.

The HMS Trent’s visit led Venezuela to begin military exercises a day earlier in the eastern Caribbean near its border with Guyana as the Venezuelan government presses its claim to a huge swath of its smaller neighbor.

Brazil’s Ministry of Foreign Affairs expressed concern Friday about the situation and urged the two South American countries to return to dialogue. It said other nations should avoid “military activities” that support either side.