Russian cosmonauts have discovered new cracks in a segment of the International Space Station that could widen, a senior space official has said, the latest in a series of setbacks.
"Superficial fissures have been found in some places on the Zarya module," Vladimir Solovyov, chief engineer of rocket and space corporation Energia, told RIA news agency.
"This is bad and suggests that the fissures will begin to spread over time."
He did not say if the cracks had caused any air to leak.
The space official has said previously that much of the International Space Station's equipment is starting to age and has warned there could be an "avalanche" of broken equipment after 2025.
The space station has suffered several recent incidents. Russian officials last month said a software glitch - along a possible lapse in human attention - were to blame for throwing the ISS out of control.
Jet thrusters on the Russian research module Nauka inadvertently reignited a few hours after it had docked, causing the entire orbital outpost to pitch out of its normal flight position with seven crew members aboard.
Roscosmos, Russia's space agency, also reported last month a drop in pressure in the Zvezda service module, which provides living quarters for crew members on the ISS that was caused by an air leak.
The Russian space agency, Roscosmos, has said it will remain part of the ISS until 2024 and that it is open to extending its participation beyond then.
Meanwhile Elon Musk's SpaceX company's 23rd resupply mission to the station has docked, with NASA astronaut Shane Kimbrough tweeting about its arrival.
"We have a new visitor on the Space Station," he wrote.
"The SpaceX Dragon cargo vehicle just arrived this morning loaded with science and goodies. Time to unpack!"
Those goodies included some birthday surprises for NASA astronaut Megan McArthur, who is celebrating her 50th birthday floating above the Earth.
"No one's ever sent me a spaceship for my birthday before. I appreciate it," she said.
The payload aboard the Dragon included ice cream for McArthur and the six other crew aboard the station along with lemons, tomatoes and avocados.
Also on board was scientific equipment to take retinal images of the astronauts to document visual issues observed from those who've been to space and cress plants to study the stress they show when grown under microgravity conditions.