WASHINGTON (NYTIMES) - As Russian troops press ahead with a grinding campaign to seize eastern Ukraine, the nation's ability to resist the onslaught depends more than ever on help from the United States and its allies - including a stealthy network of commandos and spies rushing to provide weapons, intelligence and training, according to US and European officials.

Much of this work happens outside Ukraine, at bases in Germany, France and Britain, for example.

But even as the Biden administration has declared it will not deploy US troops to Ukraine, some CIA personnel have continued to operate in the country secretly, mostly in the capital, Kyiv, directing much of the massive amounts of intelligence the United States is sharing with Ukrainian forces, according to current and former officials.

At the same time, a few dozen commandos from other Nato countries, including Britain, France, Canada and Lithuania, have also been working inside Ukraine. The United States withdrew its own 150 military instructors before the war began in February, but commandos from these allies either remained or have gone in and out of the country since then, training and advising Ukrainian troops and providing an on-the-ground conduit for weapons and other aid, three US officials said.

Few other details have emerged about what the CIA personnel or the commandos are doing, but their presence in the country hints at the scale of the secretive effort to assist Ukraine that is underway and the risks Washington and its allies are taking.

Ukraine remains outgunned, and on Saturday (June 25), Russian forces unleashed a barrage of missiles on targets across the country, including in areas in the north and west that have been largely spared in recent weeks.

US President Joe Biden and allied leaders are expected to discuss additional support for Ukraine at a meeting of the Group of 7 industrialised nations that begins in Germany on Sunday and at a Nato summit in Spain later in the week.

Shortly after Russia invaded Ukraine in February, the Army's 10th Special Forces Group, which before the war had been training Ukrainian commandos at a base in the country's west, quietly established a coalition planning cell in Germany to coordinate military assistance to Ukrainian commandos and other Ukrainian troops. The cell has now grown to 20 nations.