HANOI - Vietnamese President Truong Tan Sang left Hanoi on Thursday to pay a five-day official visit to Russia at the invitation of his Russian counterpart Vladimir Putin, reported local Nhan Dan (People) newspaper on Thursday.

The visit, the first by Sang in his position, is expected to deepen the all-sided strategic partnership between the two countries.

Vietnam and Russia officially established diplomatic ties on Jan 30, 1950. The two countries signed a joint declaration on Vietnam-Russia strategic partnership in March 2001.

Over the years, bilateral all-sided cooperation has finely developed. Two-way trade turnover reached $1.98 billion in 2011, and $918 million in the first five months of this year.

As of May 2012, Russia has 78 projects in Vietnam with a total investment of $919 million

Vietnam's investment in Russia has increased rapidly, from $100 million in 2008 to $776 million at present.

Since 2008, the two countries have established a mechanism on annual strategic diplomatic, security and defense dialogue at the deputy foreign ministerial level. So far, the two countries have signed more than 60 bilateral documents, which have provided legal framework for developing bilateral ties.