* N.Korea moves aircraft to bolster east coast defences
* China says war would have no winner
* U.S. general says economic, diplomatic pressure continues
SEOUL/BEIJING, Sept 26 (Reuters) - North Korea has boosted defences on its east coast, a South Korean lawmaker said on Tuesday, after Pyongyang said U.S. President Donald Trump had declared war and that it would shoot down U.S. bombers flying near the peninsula.
Tensions have escalated since reclusive North Korea conducted its sixth and most powerful nuclear test on Sept. 3. Bellicose rhetoric has reached a new level in recent days with leaders on both sides exchanging threats and insults.
North Korean Foreign Minister Ri Yong Ho said on Monday that Trump's Twitter comments that leader Kim Jong Un and Ri "won't be around much longer" if they acted on their threats amounted to a declaration of war and that Pyongyang had the right to take countermeasures.
South Korean lawmaker Lee Cheol-uoo, briefed by the country's spy agency, said North Korea was bolstering its defences by moving aircraft to its east coast and taking other measures after U.S. bombers flew close to the Korean peninsula last weekend.
Lee said the United States appeared to have disclosed the flight route of the bombers intentionally because North Korea seemed to be unaware.
Ri, the foreign minister, said on Monday North Korea's right to countermeasures included shooting down U.S. bombers "even when they are not inside the airspace border of our country".
In Washington on Tuesday, the top U.S. military officer, Chairman of the Joint Chiefs of Staff General Joseph Dunford, said he had not seen a change in the military posture of North Korean forces despite the heightened rhetoric.
Dunford added that Pyongyang will have a nuclear-capable intercontinental ballistic missile "soon" and it was only a matter of a "very short time".
Speaking at his Senate reappointment hearing, Dunford said "the military dimension today is in full support of the economic and diplomatic pressure campaign" that Secretary of State Rex Tillerson is leading on North Korea. Dunford made clear that military options are available to Trump if that pressure fails.
'CAPABILITY TO DETER'
During a visit to India, U.S. Defense Secretary James Mattis said diplomatic efforts continued.
"You have seen unanimous United Nations Security Council resolutions passed that have increased the pressure, economic pressure and diplomatic pressure, on the North, and at the same time, we maintain the capability to deter North Korea's most dangerous threats," he told reporters in the Indian capital.
White House spokeswoman Sarah Sanders denied on Monday that the United States had declared war, calling the suggestion "absurd".
Speaking in Beijing, Chinese Foreign Ministry spokesman Lu Kang said war on the Korean peninsula would have no winner.
"We hope the U.S. and North Korean politicians have sufficient political judgment to realise that resorting to military force will never be a viable way to resolve the peninsula issue and their own concerns," Lu said.
"We also hope that both sides can realise that being bent on assertiveness and provoking each other will only increase the risk of conflict and reduce room for policy manoeuvres. War on the peninsula will have no winner."
Chinese Foreign Minister Wang Yi, speaking on the sidelines of a U.N. meeting in New York, said the situation on the Korean peninsula was at a very dangerous stage, the foreign ministry said on Tuesday.
The urgent task was to prevent North Korea's nuclear and missile programmes from progressing to avoid a further escalation in tensions and especially to prevent resorting to arms, Wang added.
China's fuel exports to North Korea fell in August, along with iron ore imports from the isolated nation, as trade slowed after the latest U.N. sanctions, but coal shipments resumed after a five-month hiatus, customs data showed on Tuesday.
South Korean President Moon Jae-in urged Kim Jong Un to resume military talks and reunions of families split by the 1950-53 Korean War to ease tension.
"Like I've said multiple times before, if North Korea stops its reckless choices, the table for talks and negotiations always remains open," Moon said.
He was speaking at a event to mark an Oct.4, 2007, summit declaration promoting goodwill signed between then-South Korean president Roh Moo-hyun and his North Korean counterpart, Kim Jong Il, Kim Jong Un's father.
In Moscow, Russia's Foreign Ministry said it was working behind the scenes to find a political solution and that using sanctions against North Korea was almost exhausted.
U.S. Air Force B-1B Lancer bombers escorted by fighter jets flew east of North Korea in a show of force after a heated exchange of rhetoric between Trump and Kim.
North Korea has been working to develop nuclear-tipped missiles capable of hitting the U.S. mainland, which Trump has said he will never allow.
The United States and South Korea are technically still at war with North Korea after the 1950-53 conflict ended in a truce and not a peace treaty.
(Additional reporting by Michelle Nichols at the UNITED NATIONS, Dmitry Solovyov in MOSCOW and Malini Menon in NEW DELHI, Idrees Ali in WASHINGTON; Writing by Paul Tait and Ben Blanchard; Editing by Nick Macfie and Clarence Fernandez)