In addition to German concerns about the gas supply, there will be a three-day freeze on deliveries of Russian gas at the end of August.
The Russian gas company Gazprom announced that no gas will be transported to Germany through the Nord Stream 1 Baltic Sea pipeline from August 31 to September 2 due to maintenance on a turbine.
Ukrainian President Volodymyr Zelenskyy then accused Moscow of using energy for blackmail.
"Russia only needs these pipelines to create problems in Europe, not to help with gas," he said on Friday.
The sooner the European states made themselves independent of Russian energy, the sooner they would get through the winter in peace.
Without naming FDP Vice Wolfgang Kubicki, Selenskyj spoke of “absurd statements” in Germany about putting Nord Stream 2 into operation.
Russia claims to have shot down drones
On the annexed peninsula of Crimea, the Russian air defense was active on Friday for the second evening in a row and allegedly shot down drones.
Sevastopol, the home port of the Russian Black Sea Fleet, and the seaside resort of Yevpatoria were named as places.
Observers did not rule out that the Ukrainians would use it to test Russian air defenses before possible attacks.
For the Eastern European country, Saturday marks the 178th day of resistance against the Russian invasion.
US Secretary General António Guterres wanted to visit Istanbul on Saturday after stops in Ukraine and Moldova.
The ships that export grain from Ukrainian ports are checked there.
Three days gas stop for maintenance of a turbine
As announced by Gazprom, the only functioning turbine at the Portovaya compressor station will be checked and overhauled.
This should be done in cooperation with specialists from Siemens Energy.
Siemens Energy did not comment on the announcement.
A spokesman for the Federal Network Agency said that the situation was being monitored in exchange with the gas industry and the Federal Ministry of Economics.
Ukraine offered its pipeline system as an alternative.
Gas flow through Nord Stream 1 is currently at 20 percent of capacity.
Gazprom promised that this amount of gas, around 33 million cubic meters per day, should continue to flow after the stop.
Germany wants to reduce dependence on Russian natural gas because of the Russian attack on Ukraine.
Other suppliers are being sought to fill the storage tanks for the heating season.
On Friday, Kubicki had called for Russian gas to be obtained through the finished but unused Nord Stream 2 pipeline.
He was heavily criticized for this, because the pipeline is seen as Moscow's instrument for making Germany more dependent on Russia.
Russian anti-aircraft defenses active in Crimea
Crimea, annexed by Russia in 2014, is becoming increasingly insecure as a rear space for Russian troops attacking in southern Ukraine.
Last week there were devastating explosions at the Saki air base near Yevpatoria in the west of the Crimean peninsula, destroying numerous Russian warplanes.
The anti-aircraft defenses hit their targets over Sevastopol, said the city's Russian head of administration, Mikhail Rasvoschajew.
"Like many other residents, I heard explosions over the center," he wrote on Telegram.
"Probably drones." Unverified online video purporting to be from Sevastopol and Yevpatoria showed tracers of anti-aircraft fire.
Drones were allegedly shot down over the city of Kerch and the Belbek military airfield near Sevastopol on Thursday evening.
Ukrainians donate better satellite imagery to their army
Thanks to arms deliveries from abroad, the Ukrainian army has changed its tactics in recent weeks: With long-range multiple rocket launchers, it eliminates Russian ammunition depots, transport routes and command centers far behind the front.
Thanks to a fundraising campaign, the Ukrainian army now has fast access to high-precision satellite images.
The combination of reconnaissance images with modern weapons opens up new possibilities in the fight against Russia, said Defense Minister Oleksiy Resnikov.
According to the contract with the Finnish provider ICEYE, the Ukrainian government can use a radar satellite around the clock, which also provides images at night or in clouds.
The money was raised through a fundraising campaign launched by TV presenter Serhiy Prytula in Ukraine.
US increases military aid
The US government announced further military aid for Ukraine of around 775 million US dollars (around 772 million euros).
The planned aid package will include 15 ScanEagle surveillance drones, 40 mine-protected vehicles and 16 self-propelled howitzers.
This also includes ammunition for Himar's multiple rocket launchers.
This brings US military aid to a total of $10.6 billion since the beginning of US President Joe Biden's tenure.
That will be important on Saturday
UN Secretary-General Guterres plans to visit the Coordination Center for Ukrainian Grain Exports in Istanbul on Saturday.
The United Nations and Turkey reached an agreement with Russia and Ukraine in July.
It has enabled ships from three Ukrainian ports to transport grain again since the beginning of August.
Because of the war, the ports had been blocked since February.
Guterres visited the port of Odessa on Friday.
In Istanbul, ships and cargo are checked on the outward and return journey.