A foreign ministry spokesman confirmed to AFP that the summons for the charge d'affaires had taken place in Berlin, after the ministry's director general for Asia and the Pacific wrote about it on Twitter.

In her tweet, Petra Sigmund quoted Germany's representative for East Asia and the Pacific, Martin Thuemmel, as saying that Berlin condemned the executions "most strongly" and called on Myanmar to reinstate the moratorium on the use of the death penalty "and end violence and repression".

The words echo the condemnation the German foreign ministry issued earlier this week. It said it was "appalled" by the executions, which showed "the junta's contempt for the strong democratic aspirations of the people of Myanmar".

The executions announced Monday are Myanmar's first in decades and have heightened fears that more will follow, prompting calls for tougher international measures against the already-isolated junta.

Among the four executed were Phyo Zeya Thaw, a former lawmaker from Aung San Suu Kyi's National League for Democracy (NLD) and veteran democracy activist Kyaw Min Yu -- better known as "Ko Jimmy".

Both were sentenced to death under anti-terrorism laws.

Myanmar's junta has lashed out against international condemnation of its use of capital punishment, saying the four executed prisoners "deserved many death sentences".