TAIPEI (Reuters) -Taiwan's military held an early morning air defence drill on Thursday to test its response and engagement procedures, ahead of a trip by President Lai Ching-te at the end of the week to the Pacific that will include U.S. stopovers.

China is likely to launch military drills in the coming days near Taiwan, using Lai's upcoming trip to the Pacific and scheduled U.S. transit as a pretext, according to assessments by Taiwan and regional security officials.

China claims democratically governed Taiwan as its own territory and says Lai is a "separatist". Lai says only Taiwan's people can decide their future and has repeatedly offered talks with Beijing that have been rebuffed.

Taiwan's air force command said in a statement that made no mention of Lai's overseas trip that for a two-hour period starting from 5 a.m. (2100 GMT Wednesday) aircraft, ships and missile systems were involved in an "overall air defence battle plan exercise".

The drill was to "strengthen the overall effectiveness of air defence operations and to test the response and engagement procedures of the air defence forces", it added.

"In the face of changes in the enemy situation, we will continue to enhance defence resilience through various practical training to anticipate potential threats and challenges and ensure air defence security," the command said.

The defence ministry told Reuters separately that it was a regular drill carried out quarterly.

Reuters correspondents in the northern Taipei suburbs reported seeing and hearing fighter jets in the skies as dawn broke.

China has carried out two rounds of major war games around Taiwan so far this year, and on a daily basis flies aircraft and sends ships into the skies and waters around Taiwan.

Taiwan has also complained of Chinese balloons flying near the island in what the government says is a pattern of harassment by Beijing.

On Thursday, the ministry said the previous day it had spotted two Chinese balloons flying out at sea to the north of Taiwan, at distances of 60 nautical miles (111 km) and 88 nautical miles (163 km) from the port city of Keelung.

Lai will leave on Saturday. A formal announcement of his U.S. stopovers could come as soon as Friday, according to sources.

Late Wednesday, the presidential office said that if China were to use Lai's trip as an excuse to launch military exercises, "it would be a blatant provocation of the status quo of peace and stability in the region".

The same day, China's government said such transit stops were "essentially provocative acts that violate the one-China principle".

(Reporting by Ben Blanchard and Yimou Lee; Additional reporting by Roger Tung; Editing by Stephen Coates)

By Ben Blanchard and Yimou Lee