The 20 photographs of the week

The best photojournalism of the week came from Ukraine and also from the streets of Caracas and Aleppo. Here, a member of a pro-Russian force holds a gun during the seizure of the Ukrainian corvette Khmelnitsky in Sevastopol, Crimea Photograph: Andrew Lubimov/AP

In a photograph by regular contributor to this gallery Dimitar Dilkoff, armed men, believed to be Russian servicemen, stand guard outside a Ukrainian military base in Perevalnoye in Crimea Photograph: Dimitar Dilkoff/AFP

Demonstrators clash with police during a protest against Venezuelan President Nicolas Maduro, in Caracas. Several hundred Venezuelans marched against 'Cuban interference' Photograph: Juan Barreto/AFP

Ian Bird took aerial photographs of big wave surfing on the 'Ours' surf break off Cape Solander, Sydney. International surfers took advantage of the huge waves caused by the recent tropical cyclone Lusi off the east coast of Australia to ride the dangerous surf break known as 'Ours' Photograph: Ian Bird/Rex

Siegfried Modola continued his powerful work from Bangui this week. Here, a former soldier of the Armed Forces of the Central African Republic walks down a flight of stairs near an unmaintained swimming pool within the crumbling former palace of late self-proclaimed Emperor Jean-Bedel Bokassa Photograph: Siegfried Modola/Reuters

Relatives of Chinese passengers aboard missing Malaysia Airlines Flight MH370 watch a news programme about the plane as they wait for more official information at a hotel ballroom in Beijing, China Photograph: Alexander F Yuan/AP

Students from the Benigno Aquino high school walk on a mural depicting the missing Malaysia Airlines plane at their campus at Makati, Philippines Photograph: Bullit Marquez/AP

A man inspects the damage caused by what activists said were barrel bombs dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo Photograph: Ammar Abdullah/Reuters

Afghan refugee children are photographed by Muhammed Muheisen on the outskirts of Islamabad. For more than three decades, Pakistan has been home to one of the world's largest refugee communities: hundreds of thousands of Afghans who have fled the repeated wars and fighting in their country Photograph: Muhammed Muheisen/AP

Residents Luiza, Janubie, Leiticia, Anacleide and Lucas sit beneath an overpass near their homes in the unpacified Complexo da Mare slum complex, one of the largest favela complexes in Rio Photograph: Mario Tama/Getty

Not taken this week but this picture is included in the 20 photos as photographer Nan Goldin is interviewed by Sean O'Hagan in this week's New Review. Elephant Mask, Boston, 1985, is also in the book Nan Goldin: Eden and After published by Phaidon next week
Photograph: Nan Goldin

Indian labourer Hanif Muhammad washes chemicals off his legs after a process called fleshing at a leather tannery workshop in Kolkata, India. More images from this series by Piyal Adhikary can be seen here Photograph: Piyal Adhikary/EPA

Mo Farah is helped up by medics after he collapsed when finishing in second place at the 2014 New York City Half Marathon Photograph: Rich Schultz/Getty

South African Paralympic athlete Oscar Pistorius stands beside his sister Aimee on the 13th day of his trial for the murder of his girlfriend Reeva Steenkamp at the North Gauteng high court in Pretoria Photograph: Leon Sadiki/AFP

A woman plays bingo at Carlton Bingo Hall in Orrell Park, Liverpool, as the chancellor, George Osborne, announced tax breaks for bingo halls in the UK Photograph: Christopher Furlong/Getty

The silhouettes of two men are reflected in a window of a building at the Pudong financial district in Shanghai. China pledged this week that it will make sure that 60% of its cities meet national pollution standards by 2020 Photograph: Carlos Barria/Reuters

An ultra-Orthodox Jewish girl sits in a cage wearing a fancy dress costume to mark the Purim festival in Bnei Brak, Israel. The holiday of Purim commemorates the Jews' salvation from genocide in ancient Persia, as recounted in the Book of Esther Photograph: Ariel Schalit/AP

Soldiers from the Israeli Army Artillery battery unit are deployed on alert near the border with Syria in the Israeli-annexed Golan Heights. Israel launched air raids against Syrian army positions and issued a stark warning to Damascus just hours after a bomb wounded four of its soldiers Photograph: Menahem Kahana/AFP

Protesters take cover behind a shield during clashes with riot police following the funeral of Jawad Ahmed Al-Haawi in Sitra, Bahrain. Al-Haawi died in hospital after developing respiratory complications which his relatives claim were due to the inhalation of poisonous teargas that riot police used during a protest in March Photograph: Mohammed Al-Shaikh/AFP

In this final image, we return to Simferopol in Ukraine where workmen change the lettering on the parliament building to a sign that reads 'Crimean Autonomous Council' Photograph: Dan Kitwood/Getty