The threatened US military strike against Syria has increased the risk of derailing the upcoming G20 summit, which should be focused on the global economy.

It is apparent summit host Russia has set fostering economic growth and job creation as the primary objectives, but US President Barack Obama is bound to make use of this chance to bring the Syria issue to the summit, seeking support for Washington's military plans for Syria.

Firstly, Obama has to persuade his war-weary alliance to support his decision. And he is facing a tough job.

The British parliament decided not to join the United States in military moves against Syria, a big blow for Obama. French President Francois Hollande, who had supported military actions, changed his mind and said French lawmakers should be consulted before an attack.

As to Germany, its leaders remain prudent ahead of the upcoming September 22 general election.

Secondly, Obama has to overcome embarrassment in order to talk with his Russian counterpart over Syria.

Obama had snubbed Putin by refusing a bilateral meeting on the sidelines of the summit following Putin's decision to grant former National Security Agency contractor Edward Snowden temporary sanctuary.

The president has to make a "U-turn" at the summit and seek an opportunity to talk with the Russian leader.

Taking into account Putin's clear policy on Syria and strong opposition to US-led military action, Obama will have a tough job explaining why Washington should take the action and risk jihadists taking control of Syria.

US Secretary of State John Kerry said Tuesday: "Let's hope that at the summit (they) might have some change of heart," implying a softened signal for Russia.

Thirdly, Obama is bound to talk with other leaders from the international community at the summit.

US-led unilateral military action could send a dangerous signal to the world, since it sidelines the UN Security Council.

UN Secretary General Ban Ki-moon has made it clear an authorization from UN Security Council is a must, announcing it will be several weeks before UN investigators can identify the perpetrators of the Damascus chemical weapons attack which prompted the current US plans.

It is well established the G20 summit is a vital forum for leaders to seek more measures to boost the world economy, at a time when global economic growth lacks momentum and the deep-seated impact of the international financial crisis goes on unabated.

Therefore, it would be a pity if the United States tries to derail the summit to suit its own interests, when the international community is looking forward to a successful and effective economic response from major economies.