A pro-Turkish demonstration in Mogadishu. Photograph: Feisal Omar/Reuters

For Nairobi’s commuters, summer has brought more woes than usual. Along with the demonstrations, road accidents and downpours that frequently cause gridlock in Kenya’s capital, there has been an almost weekly shutdown as foreign VIPs fly in. “Of course people are annoyed … but some rather like it. We are getting the feeling that we are finally returning to centre stage,” said Charles Onyango-Obbo, a publisher and journalist.

Many of the visitors have been from the US, China and other nations long seen as players in the region, but an increasing number are from the Middle East, their visits underlining a dramatic twist in the centuries-old battle between foreign powers for influence, trade, resources and military assets in a strategically sensitive part of the world.

In five weeks over June and July, Kenya received Iranian ministers, delegations from Gulf monarchies and the leaders of both Turkey and Israel. Other states in east Africa have seen a similar flow of high-level officials.

Analysts are struggling to understand the potential impact of the new wave of interest from the Middle East, but it is already clear it will disrupt local diplomacy and politics as much as it has disrupted traffic, resetting alliances in new formulations determined as much by conflicts, rivalries and geopolitical interests thousands of miles away as the interests of local communities. It has the potential, too, to undermine western influence and agendas.

“There is a significant new layer of engagements,” said Ahmed Soliman, a Horn of Africa expert at London’s Chatham House thinktank.

The shift is a result of many factors. The chilly aftermath of the Arab spring, the Syrian civil war, and particularly the conflict in Yemen have all combined to push Middle Eastern states to seek advantage through alliance, trade and cultural outreach beyond their immediate neighbourhood. So, too, has intensifying rivalry between Sunni Muslim Saudi Arabia and Shia Iran, economic pressures on individual states and the arrival of new leaders keen to make their mark.

At the same time, experts say, China is more cautious than before, the US distracted, the United Nations overstretched, and the European Union weak. This has opened up new space, with commercial opportunities ranging from melon farming to port development adding to the attraction. The change is not necessarily good news for the UK and other western nations.

“Confronted by their own conflicts, [countries in the Muslim world] have decided to secure their own interests in the Horn of Africa. Whether the western interest in counter-terrorism, good governance and economic growth can find common ground … so as to sustain a momentum towards stability and coherence … is one of the great challenges that we collectively face,” wrote Alexander Rondos, EU special representative for the Horn of Africa, recently.

Sinan Ülgen, an expert at Carnegie Europe in Istanbul, said Turkey’s ultimate aims were grander: “Turkey wants to be seen as a champion of victimised people of the Islamic religion everywhere. It is about improving soft power and image. Turkey has become one of the biggest providers of humanitarian assistance in the world. That is a valuable attribute. What’s done in Somalia does not stay only in Somalia.”

There is competition. The United Arab Emirates (UAE), spurred by its own security concerns, is also moving fast to establish influence in east Africa. If Turkey is backing the ruling alliance in forthcoming Somalian elections, the UAE appears to favour opposition candidates.

“It hasn’t been recognised outside the region, but it is Middle Eastern states which will have real influence in the polls, not the US, UN, EU or UK,” said one Kenya-based veteran observer of Somali affairs.

In another development shaking up the regional status quo, the UAE is building physical bridgeheads too, opening a major military base in long-isolated Eritrea. This could accelerate the slow reintegration of the secretive, repressive state into the international community – or reverse it.

Then there is Saudi Arabia, now under the leadership of King Salman. The kingdom’s decades-old relationship with the US has chilled and its rivalry with Iran intensified in recent years. When assembling a military alliance against Houthi rebels in Yemen, who are allied with Iran, the kingdom enlisted the support of a series of east African states.

Somalia and Sudan both dumped alliances with Iran earlier this year in favour of new ties with Saudi Arabia. Somalia received pledges from Riyadh of aid worth $50m within hours of the decision. Heavily sanctioned Sudan may have gained billions – a crucial financial lifeline.

“What we are seeing is a shift in … agendas of major players in the Gulf. There’s a historical context to the relationship … but the [region] is now being seen as part of their ‘near abroad’, and an important sphere of influence,” said Soliman.

Saudi businessmen also play an important role, with several prominent in Ethiopia, the regional economic powerhouse, while the number of east African students studying in Saudi Arabia has risen dramatically in recent years.

Then there is the Saudi religious establishment, which for decades has bankrolled mosques and religious schools across the region and is blamed by many for the spread of rigorous and intolerant strands of Islam – often called Wahhabism. This is a key concern of the west, and of many local players as well.

“[Saudi Arabia] and other Gulf states have developed specific new relationships with Sudan, Somalia and Eritrea. This has generated a reaction in countries like Ethiopia and Kenya, which see behind this new tilt towards the Gulf a loss of their relative influence as well as a growing threat of Wahhabi-driven radicalisation in the region,” wrote Rondos.

One of the most active of the new players in east Africa is Israel. Benjamin Netanyahu, the rightwing prime minister, has led a push for better relations across Africa, particularly in the east, where he has reinforced ties with old allies such as Kenya.

Nimrod Goren, of the Israeli Institute for Regional Foreign Policies, said that Israel’s efforts in Africa were part of a broader desire to look for “non-traditional” allies. A recent recognition that African nations could be a source of support – not inevitable opposition – at the UN is one key factor. “It is not a new phenomenon that [Middle Eastern powers] are engaged in Africa. What is a new phenomenon is that Israel is able to play the game as well,” Goren said.

Haaretz, the Israeli newspaper, reported last week that Israel was lobbying the US and Europe to improve relations with Sudan following its shift against Iran.

Though the new dynamic is changing the region, commentators warn against writing off the major players such as China and the US just yet. “For 10 years I’ve been driving past the US embassy on my way to work. The queues [for visas] never get any shorter. Until … all the other guys have those kind of queues, they are not going to win this,” said Onyango-Obbo.