After coronavirus lockdowns that brought civil aviation to nearly a complete halt air traffic is slowly resuming in Europe as borders reopen, but tens of thousands of jobs are still hanging in the balance.

Iranian police on Wednesday questioned four people as part of investigations into a powerful explosion that killed 19 people at a Tehran clinic the night before, state media reported.

Russians are set to approve constitutional reforms on Wednesday denounced by critics as a manoeuvre to allow President Vladimir Putin to stay in the Kremlin for life.

Canada extended its entry ban for most foreigners by another month to July 31 and also prolonged its quarantine requirements in efforts to prevent imported cases of the coronavirus.

Hong Kong police said they had arrested at least 180 people Wednesday -- including seven under a new national security law -- as thousands of protesters defied a ban to rally on the anniversary of the city's handover to China.

Venezuela will hold elections in December to renew the National Assembly, the only institution in opposition hands, the electoral authority announced Tuesday.

The European Union reopened its borders Wednesday to visitors from 15 countries -- but not the virus-stricken United States, where a top health official warned the country is headed in the "wrong direction" as cases spike in multiple states.

Iran said Tuesday that the preservation of a nuclear accord depended on the scheduled end in October of a U.N arms embargo as the United States seeks to extend it..

Iranian state television is reporting an explosion from a gas leak in a medical clinic in northern Tehran has injured at least three people.

The explosion Tuesday night led to fire and state TV said firefighters were battling the blaze.

Russia warned Tuesday of an "uncontrollable escalation" as the United States presses to extend an arms embargo on Iran or impose U.N. sanctions that could kill a nuclear deal.