Just 800,000 people live in Djibouti. The former French colony is barely larger than the German state of Hesse. Yet the small country on the Horn of Africa is one of the strategically most important places in the world.

"Whoever controls Djibouti plays a decisive role," said Michael Ashkenazi from the International Center for Conversion, a think tank based in Bonn, Germany.

Djibouti is one of the main transfer points for world trade. More than 80 percent of all goods that neighbor Ethiopia imports arrive at the container port of Doraleh, one of the largest deep-water ports in East Africa. Next to this is the country's strategic proximity comes to the trouble spots in Africa, Asia and the Middle East.

"For protecting trade routes and also as a starting point for the anti-terror struggle on the Horn of Africa, Djibouti is currently probably the most important country," said Annette Weber of the German Institute for International and Security Affairs (SWP) in Berlin.

Is Beijing also eyeing Djibouti?

China also knows how important Djibouti is. Talks are already underway about a Chinese military base in Djibouti. President Ismail Omar Guelleh told the news agency AFP in May that Beijing was "welcome."

Kerry and Guelleh have affirmed their commitment to stablility in the area

But China's government is reticent to say more, confirming officially only that it planned to contribute to stability in the region. To support the fight against piracy, China has sent ships to the Somalian coast since 2008 - and since 2010 also to the Gulf of Aden near Yemen.

China hopes to win more international influence, Ashkenazi said. "In the past ten years and even before that, China has very invested heavily in Africa, not only in order to profit financially but also to gain long-term control of natural resources."

The choice of Djibouti is also due to the country's relative political stability, Ashkenazi said. Relatively stable means Guelleh has ruled since 1999 with a heavy hand. There are no open uprisings, no long-term terror, such as in neighboring Somalia.

China is planning what other industrialized countries have already been doing for years. The US has had its only military base in Africa in Djibouti since 2002. Added to this are support points for France, Japan and the EU. From here, the struggle against piracy in Somalia is coordinated.

Since 2012, ships from the EU mission EUCAP-Nestor have also been on patrol in other parts of the West Indian Ocean. Washington also controls drone strikes against Islamist terrorists in Yemen and Somalia from Camp Lemonnier in Djibouti City. China could soon also be settling into Djibouti. "That could perhaps also lead to severe disagreements with those who are already there," Weber said.

Lucrative military presence

The government of Djibouti benefits from the foreign military. "The bases are a main source of income for the country, which hardly has any other finance," Ashkenazi said. In early May, the US extended the lease on its base for at least ten years - and will pay even more in future. The base will cost around $60 million annually; until now that was about $30 million. In addition, the US finances the training of Djiboutian soldiers.

These are revenues the government needs urgently. Except for services, Djibouti's economy has almost nothing to offer - neither much in the way of industry nor valuable raw materials. Many foods have to be imported due to the hot and dry climate.

Djibouti is of key naval significance in the oil-rich region

The majority of the population has apparently not benefited so far from the lease income from abroad. Poverty is high. In 2014, UN statistics placed Djibouti 2014 only 170th among the 187 countries exhibited in its "Human Development Index," which measures various poverty factors.

The editor in chief of Pan-African News Wire in the US, Abayomi Azikiwe, is especially critical of the US military presence in Djibouti. "We have not been able to ascertain that the people of Africa's different nations have profited from it," he said. "Rather, we think that it only goes to serve the national security and economic interests of the US."

A flood of migrants

At the narrowest point, Djibouti is only 30 kilometers from Yemen, where since March Shiite Huthi rebels have been engaged in fierce battles with government troops. According to the UN, Djibouti has already taken in more than 21,000 refugees from Somalia. Added to this, refugees now come daily from Yemen. Djibouti's Foreign Minister Mahamoud Ali Youssouf told news channel CNN his country was "overwhelmed."

The refugee flows also bring with them dangers for the political stability of the small state. "The question of which violence-prone persons are coming to Djibouti, from both the Somalian Al-Shabaab militia and from the ranks of the fighters in Yemen themselves, is undoubtedly a source of disquiet for the government in Djibouti," Weber said.

The UN refugee agency, the UNHCR, says it is working on an emergency plan for the coming months to accommodate up to 30,000 migrants from Yemen in Djibouti.