POCHEON, South Korea — A huge North Korean flag disappeared behind a tower of flames and thick black smoke Friday as South Korean fighter jets and US attack helicopters fired rockets in the allies' biggest joint live-fire drills since the Korean War. The war games south of the heavily armed Korean border come amid rising animosity between the rival Koreas and are meant to mark Monday's 62nd anniversary of the start of the 1950-53 war, which ended in a truce, leaving the Korean Peninsula still technically at war. Live-fire drills by the allies are fairly routine, but using the North's national flag as part of target practice is unusual — and will be seen as a provocation by Pyongyang, which has previously threatened war for what it called South Korean insults to the country's national symbols and leadership. Still, an immediate North Korean military retaliation is unlikely. The rockets didn't hit the flag, which an analyst said might lead to a less angry North Korean response. But even a direct attack on the flag would probably only result in escalated North Korean threats because Pyongyang's struggling economy prevents it from staging any attack that could cause a war, said Koh Yu-hwan, a North Korea professor at Seoul's Dongguk University. The one-day drills, involving 2,000 troops from both countries, are intended to send a clear warning against North Korea aggression by showing US and South Korean combat readiness, South Korea's Defense Ministry said in a statement. Officials have described these as the biggest ever joint drills. They coincide with several days of joint naval exercises involving a nuclear-powered US supercarrier and separate US, South Korean and Japanese naval rescue drills. A US military spokeswoman, Jennifer Buschick, wouldn't comment on the flag, deferring to the South Korean military. A South Korean defense official, who declined to be named because of office policy, said the flag was meant to mark enemy territory during the drills, but he wouldn't comment on Pyongyang's possible reaction to use of the North Korean flag in the drills. North Korea's state media have condemned the ongoing drills as a precursor to an invasion, with the Korean Central News Agency warning that even a small clash could lead to a “full-scale nuclear war.” — AP