Chen's Air Force One official plane had been heading for Penghu, an island group in the strait, when it was targeted by the warplanes from China, the United Daily News said, quoting unidentified Chinese defense sources.

Vice President Annette Lu's plane was also targeted by Chinese fighter jets when she was flying to Penghu on October 2, the paper said.

The report came one day after Chen called for the establishment of a "buffer zone" in the strait where military aircraft and vessels from both sides must not enter without advance notice to avoid unexpected clashes.

The Air Force One with Chen onboard arrived in Penghu 15 minutes behind schedule on September 27 as 28 Chinese fighter jets were hovering over the strait, the paper said.

The gesture had been was meant to demonstrate Beijing's capability to defend its "sovereignty" over Taiwan, not to initiate any attacks, it quoted the mainland sources as saying.

A number of Taiwan's air force jets were scrambled after some of the rival warplanes had passed the hypothetical middle line of the strait, the 150-kilometer (95-mile) wide waterway separating the two rivals, it added.

Taiwan's defense authorities declined to comment on the report.

Tensions between the two sides have been rising since the re-election of the independence-leaning Chen, with Beijing renewing its long-standing vow to take the island by force should it declare formal independence.

China considers Taiwan part of its territory awaiting to be reunified despite their split in 1949 after a civil war.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.