President Volodymyr Zelenskiy says, after a Ukrainian drone attack on an oil refinery 1300km from its own borders, that his country is answering Russian strikes with "longer-range responses".
In his nightly video address, Zelenskiy did not refer directly to the attack on the Russian region of Tatarstan but said such responses were just as important as helping Ukrainians who were suffering from enemy attacks.
"Equally important is that the Russian terrorists are receiving responses to their strikes," he said.
"Each time, longer-range responses."
Zelenskiy on Tuesday signed a bill to lower the mobilisation age for combat duty from 27 to 25, a move that should help Ukraine generate more fighting power in its war.
The bill had been on Zelenskiy's table since it was approved by MPs in May 2023, and it was not immediately clear what prompted him to sign it.
Parliament has been discussing a separate bill to broadly tighten draft rules for months.
The move expands the number of civilians the army can mobilise into its ranks to fight under martial law, which has been in place since Russia launched its full-scale invasion in February 2022.
Ukrainian troops are on the back foot on the battlefield, facing a shortage of ammunition supplies with vital funding from the US blocked by Republicans in Congress for months and the European Union failing to deliver promised ammunition on time.
The signing of the legislation was not immediately announced by the president's office.
Parliament merely updated the entry for the bill on its website to read: "returned with the signature of the president of Ukraine".
Zelenskiy said last winter that he would only sign the bill if he was given a strong enough argument of the need to do so.
The Ukrainian leader said in December that the military had proposed mobilising up to 500,000 more Ukrainians into the armed forces, something he said the then-commander of the armed forces had asked for.
Since then, Ukraine has changed the head of the armed forces and the new chief, Oleksandr Syrskyi, said last week that the figure was no longer up-to-date and that it had been "significantly reduced" after a review of resources.
Zelenskiy separately signed a second bill requiring men given waivers from some military service on disability grounds to undergo another medical assessment.
A third bill he also signed aimed to create an online database of those eligible for military service.
Both those bills could potentially help the military draft more fighters.
A string of strict measures set out in an earlier draft of that bill were gutted following a public outcry.
Zelenskiy has warned that Russia may plan another offensive later in the spring or in summer, and Ukraine's troops have been scaling up their efforts to build up strong defensive fortifications along a sprawling front line.
With the initial shock of the invasion long gone, Ukraine has faced a significant reduction in the flow of volunteer fighters and numerous cases of draft evasion have been reported.
