Flooding caused by torrential rains in eastern Europe has killed three people, with a further four missing, Romanian and Bulgarian authorities said Wednesday.

In Arges in southern Romania -- one of the worst hit areas -- a 72-year-old man was swept away by floodwaters as high as two meters (six and a half feet), local authorities said.

Bulgaria's Socialists-backed Prime Minister Plamen Oresharski handed in the resignation of his cabinet Wednesday ahead of snap elections that will seek to end months of political turmoil in the European Union's poorest country.

"The resignation of the cabinet of Prime Minister Plamen Oresharski was tabled in parliament at 5:59 pm (0259 GMT) Wednesday," the parliamentary press office said in a statement.

Amnesty activists erected a symbolic wall in the heart of downtown Sofia Friday to denounce Bulgaria's "gatekeeper" role shutting migrants out of the European Union.

About 80 rights activists from 30 countries staged a silent vigil next to a two-meter-tall (6.6-feet-tall) fence symbolizing Europe's external border.

Bulgaria has identified on Friday Lebanese-French Mohammed Hassan al-Husseini as the bomber who blew up an airport bus in 2012, killing five Israeli tourists.

A joint report for the Bulgarian State Agency for National Security (DANS) and the prosecutor's office said in a statement that “the identity of the suicide bomber that carried out an attack at the Burgas Airport on the Black Sea coast was identified after DNA tests were run.”

Overwhelmed by an influx of mostly Syrian immigrants, Bulgaria has taken steps to secure its EU border -- including building a barbed-wire fence -- but now faces criticism from rights groups.

The 30-kilometer (19-mile) fence, standing three meters (10 feet) high and fortified with razor wire coils, was completed this week.

A passenger train derailed in Bulgaria on Saturday, killing the driver and injuring 15, two seriously, the transport ministry and hospital sources said.

The train with some 160 passengers aboard was travelling from Sofia to Varna in the east of the country when it came off the tracks and crashed into a building, according to Kristian Krastev, head of the state-owned railway network.

Bulgaria was hosting joint navy drills with fellow NATO members in the Black Sea on Friday, as the United States tries to reassure a region worried about Russia's intervention in Ukraine.

Navy ships from the United States as well as Greece, Romania and Turkey, and four destroyers from NATO's maritime immediate reaction force and a US patrol aircraft, were to take part in the exercises, Bulgaria's defense ministry said.

The Bulgarian prime minister has announced he will resign at the end of July, ahead of an early election aimed at ending months of political crisis.

Prime Minister Plamen Oresharski said on Thursday that he would submit his resignation to parliament "on July 23, 24 or 25," and that lawmakers "will be able to vote" on the decision.

Around a thousand tourists from Romania have been left stranded by flash floods in Bulgaria which left 14 dead around the Black Sea resort of Varna, the Romanian government said on Saturday.

Most of the Romanians affected were in the seaside town of Albena, near Varna.

Flash floods in Bulgaria have killed at least 14 people, including two children, with others missing after torrential rains lashed the east of the country, authorities said Friday.

The worst hit was the Asparuhovo neighborhood of the Black Sea port city of Varna, where at least 11 people including two children perished, local authorities said.