Reuters/Seoul

North Korea again fired short-range rockets into the sea off its east coast on Wednesday, South Korean media reported, latest in a flurry of tests ahead of this week's visit by Chinese President Xi Jinping to Seoul.

China, the North's main benefactor, has repeatedly come under pressure from both South Korea and the United States over the past decade to use its influence to convince Pyongyang to give up its nuclear and missile programmes.

Xi, who is due to arrive in Seoul on Thursday in his first visit to South Korea since taking office last year, is reciprocating Park's visit to China a year ago.

North Korea, which tested two short-range ballistic missiles on Sunday in violation of a U.N. ban, is expected to be high on the agenda when Xi meets his South Korean counterpart, Park Geun-hye.

The secretive North's nuclear and missile programmes, and its plans to hold a fourth nuclear test, will dominate the agenda, officials in Seoul said.

China is usually very guarded in its opinion on North Korea's nuclear programme but Pyongyang's three nuclear tests and several rounds of sabre rattling have tested Beijing's support.

The South's Yonhap news agency quoted a military official as saying the North test-fired two projectiles on Wednesday that flew some 180 km (110 miles).

A South Korean defence ministry official was unable to confirm what kind of weapon was fired on Wednesday, but said they were assumed to be 300 mm rockets launched from one of the North's many Multiple Rocket Launchers.

Chinese Foreign Ministry spokesman Hong Lei said he noted the news, but added that there was "no basis" to any suggestion the rocket launches were connected with Xi's trip.

"We hope all sides can do more to alleviate the situation on the peninsula and jointly safeguard its peace and stability," he told a daily news briefing in Beijing.

U.N. resolutions prohibit North Korea from procuring and using ballistic missile technology, but short range rocket launchers are not included in the ban.