US Secretary of State Rex Tillerson has called on NATO allies to step up their contributions to the Western alliance's budget by the end of 2017.

Ahead of a NATO foreign ministers meeting in Brussels on Friday, Tillerson called on NATO partners to agree with President Donald Trump to make spending boost plans during the alliance’s summit in May in Brussels.

"Our goal should be to agree at the May leaders' meeting that by the end of the year all allies will have either met the pledge guidelines or will have developed plans that clearly articulate how...the pledge will be fulfilled," Tillerson told reporters at the NATO headquarters.

Tillerson is attending his first meeting of NATO foreign ministers in Brussels on Friday, which was moved forward to ensure he would participate in it.

NATO Secretary General Jens Stoltenberg will chair talks that will discuss ways of preventing the trans-Atlantic military alliance from falling apart.

NATO Secretary General Jens Stoltenberg (C) greets US Secretary of State Rex Tillerson upon his arrival for a North Atlantic Council (NAC) meeting at the level of Foreign Ministers, at NATO headquarters in Brussels on March 31, 2017. (Photo by AFP)

The ministers would discuss "fair burden sharing to keep the trans-Atlantic bond strong" and "stepping up NATO efforts to project stability and fight terrorism,” Stoltenberg said on Friday.

Trump wants "real progress" among NATO allies to increase their spending towards the minimum criteria of two percent of their economic output by the end of the year, US Vice President Mike Pence told European chiefs in February.

“America will do our part but European defense requires European commitment as much as ours... The president expects real progress by the end of 2017,” Pence said after talks with Stoltenberg in Brussels.

President Trump, who once denounced the Western military alliance as "obsolete", has said NATO members should either pay for US military support or rely on their own military might at the time of war.

German Chancellor Angela Merkel (L) and US President Donald Trump look on during a meeting at the White House, March 17, 2017. (Photo by AFP)

Trump reportedly urged German Chancellor Angela Merkel during their meeting in Washington, DC earlier this month to pay hundreds of billions of dollars Berlin owes to NATO.

Trump handed the bill — thought to be for more than £300 billion (US$375 billion) — to Merkel during the meeting, the Sunday Times reported, citing an unnamed German minister, who called the request “outrageous.”

During the meeting, the new US president reportedly criticized Germany for not making adequate contributions to the military alliance, forcing the US to burden larger spending than its fair share.

Under a 2014 agreement, each NATO member should set aside two percent of their GDP for military purposes. However, only the US, Britain, Estonia, Greece and Poland have so far been able to meet the target.